U.S. Army Ordnance Research and Development in World War II: A Review

Publisher’s Note

Originally published by Merriam Press in book form in 1988. There were seven printed editions through 2020. The last edition was released under ISBN 978-1-71658-899-0. Each successive edition improved design and production quality as well as adding additional illustrations and photographs. This version encompasses the original text and all of the illustrations and photographs added to the various editions.

The material published in this article is a complete reprint of the text of Chapter 1 (“Review of Ordnance Research and Development in World War II”) of a manuscript in the National Archives (Records Group Number 156, Box A746). The author was not identified on the copy I worked from, although it seems likely this manuscript was written by an officer (or historian) of the U.S. Army’s Ordnance Department, since the author obviously had access to most, if not all, Ordnance Department records.

While no date is given as to when the manuscript was originally prepared, it would seem likely that it was written not long after World War II. It was not declassified until 27 September 1958.

Although much more could obviously be written about the Ordnance Department’s research and development role in World War II, this work is certainly of immense value because of its almost exclusive use of original source documents, as well as having been written shortly after the events occurred.

Introduction

In addition to its responsibility for the procurement, supply, and maintenance of the weapons and vehicles required by the U.S. Army in World War II, the Ordnance Department also had the duty of designing and developing such weapons and vehicles.

Of necessity the research and development activities of the Ordnance Department went somewhat beyond those of designing and developing actual materiel. Development of improved gun tubes, for example, required inquiry into the properties of the steel which went into these gun tubes. Metallurgical research was also necessary in the study of armor plate for combat vehicles.

Since most of the equipment produced by the Ordnance Department contained moving parts and much of it was powered by gasoline or diesel engines, research into fuels and lubricants was imperative.

Since virtually all vehicles rolled on rubber and many other types of equipment utilized rubber components, Ordnance had a vital interest in the development of synthetic substances intended to replace natural rubber.

Its heavy requirements for explosives also forced Ordnance into an examination of the chemistry of such compounds.

While it exercised supervision over a wide range of research projects, the Ordnance Department used its own facilities primarily for the development of improved models of existing weapons and vehicles. Outside agencies, principally the National Defense Research Committee, performed, or arranged for performance of, most of the basic and applied research deemed necessary. Exceptions were military rockets and recoilless weapons evolved primarily by the Ordnance Department with the assistance of the commercial organizations which later produced them in quantity, and steel.

That Ordnance concentrated its physical resources on development rather than research is indicated by the fact that Ordnance had little to do with the three major wartime discoveries in the munitions field—the atomic bomb, radar, and VT fuze.

World War II was fought, largely, with the weapons, ammunition, and vehicles, or modifications of such materiel, with which the Army was equipped in 1940. These modifications, which permitted artillery and small arms to shoot further, faster, and with more deadly effect; permitted tanks to maneuver more swiftly, return enemy fire easier, and return more effective fire; permitted motor transport vehicles to move troops and supplies more rapidly, and assisted the Army in many other ways to become a more efficient fighting force—were the primary occupation of the Ordnance research and development organization. In addition, many new types of materiel were added to the list of standard equipment as part of the continuing effort to provide an adequate tool for any job the Army was required to perform.

On 30 June 1940, the Ordnance list of standards contained about 1,200 items (including substitute standard and limited standard items).[1] At the end of the war more than 1,800 items were listed.[2]

The Situation in 1940

At the beginning of the defense period, 30 June 1940, research and development in the Ordnance Department was conducted jointly by Industrial Division and Technical Staff, with the understanding that Technical Staff would confine itself to “basic research and. technical research problems of broad application. not relating directly to authorized development projects.”[3]

Authorized development projects were within the province of Industrial Division. This division of functions in the research field was predicated on the theory that it is possible to separate basic research from applied research.

Although depot supplies of ordnance were not sufficient to arm and equip the military force mobilization planners had in mind for the future, the Ordnance Book of Standards, on 30 June 1940, listed many formidable weapons which had either been held over from World War I or developed during the peace years.

Standard artillery weapons included a variety of field guns, howitzers, special aircraft, anti‑aircraft, anti‑tank, tank, railway and seacoast artillery, and mortars.

The 155mm M1 field artillery piece was ready for immediate manufacture. Howitzers included the 75mm Pack Howitzer M1A1, the 105mm M2A1, and the 240mm M1918‑M1A1.

The standard aircraft artillery was the 20mm M1 and AN‑M2, and 37mm M4.

Standard anti‑aircraft guns of the 37mm M1A2, 3-inch M3, 90mm M1, and 105mm M3 types had proven their value to both the Ordnance Department and the Service Boards of the interested combat branches and were ready for production.

The standard anti‑tank guns were the 37mm M3 and 75mm M1897A2.

The standard tank gun was the 37mm M5. Also available for any use that might be made of them were the 8-inch Mark VI, Modification 2, railway gun, and the 8-inch Mark VI, Modification 3A2, and 16-inch Mark I seacoast rifles.

The 60mm M2 and 81mm mortars completed the list of standard artillery.[4]

Under development were a mobile 75mm gun designed for use as either an anti‑aircraft or anti‑tank weapon,[5] a mobile 4.7-inch anti‑aircraft gun,[6] a 155mm howitzer of monobloc construction,[7] an 8-inch howitzer, and a 240mm howitzer felt to be an improvement over the standard weapon.[8] Artillery development between wars had followed loosely the recommendations of the Westervelt Board Report of May 1919.[9]

In the small arms field a list of reliable rifles, machine guns, submachine guns, aircraft guns, and pistols gave evidence that many weapons acceptable to the Infantry Board and the Air Corps would be available as soon as production facilities could turn them out. On 30 June 1940 three rifles were standard—the caliber .30 M1 (Garand), M1903 (Springfield), and the M1918A2 (Browning Automatic).

For ground use, two Browning machine guns, the caliber .30 M1917A1 and the caliber .50 M2, were available. Other Browning machine guns, the caliber .30 M1919A4, and caliber .30 M2, were deemed suitable for use in aircraft.

The Thompson caliber .45 M1928A1 submachine gun, a military adaptation of the “Tommy” gun (which figured in many gangland killings) was also standard.

The standard sidearm was the caliber .45 M1911A1 automatic pistol.[10]

Although active development of the caliber .30 carbine did not begin until September 1940, this weapon had been under discussion since March 1938, at which time the Chief of Infantry had suggested development.[11]

To this, and subsequent suggestions, the Ordnance Department replied that the ammunition supply problems engendered by development of such a weapon would outweigh its advantages.[12] Development, however, was ordered by the Adjutant General in August 1940.[13]

None of the rocket weapons, such as the “Bazooka,” or recoilless rifles were yet under consideration.

Only a handful of combat vehicles had been standardized by 30 June 1940, although several were in various stages of development. At that time the Light Tank M2A4, weighing 12 tons and mounting a 37mm gun and four caliber .30 machine guns, was ready for production as was the Medium Tank M2A1 which weighed 20 tons and also mounted a 37mm gun and carried eight machine guns of caliber .30.

Also standard were Combat Cars Ml and M2 (re‑designated Light Tanks, M1A2 and M1A1 in July and August 1940 and declared obsolete in 1942) and Scout Car M3A1.[14]

The most important development under way in June 1940 was the modification of the standard medium tank by the addition of armor plate and a 75mm gun.[15] The resulting tank was later standardized as the M3 (“General Grant,” with gun in the right sponson) and the M4 (“General Sherman,” with gun in turret).

The meeting of the Ordnance Committee which approved development of a more powerful medium tank also approved work on a 50 ton heavy tank and a 75mm Gun Motor Carriage.[16]

The Half‑Track Car T14 was in the final stages of development and was standardized as the M2 in the late summer of 1940.

Steps were being taken, too, to increase the weight of armor carried by the standard light tank.[17]

Other developmental projects nearing completion at this time were those with respect to vehicles standardized in September and October 1940 as Half‑Track Personnel Carrier M3 and 81mm Mortar Carrier M4.[18]

Since a gun cannot be effectively used unless there is ammunition for it, standard or experimental ammunition was available for all weapons standard on 30 June 1940.

In addition, a wide variety of reliable mechanical time fuzes, as well as other fuzes, were ready for manufacture.

Aircraft bombs ranging in size up to 2,000 pounds were standard.

Six types of cannon powder, developed by DuPont, Hercules, and Picatinny Arsenal, and three types of high explosives—tetryl, TNT, and Explosive D (Ammonium Picrate)—were standard for use in artillery ammunition. A nitrocellulose blend was the standard propellant for rifle and machine gun ammunition.[19]

Development was proceeding in connection with ammunition for experimental weapons, while attempts were also being made to develop more efficient ammunition for standard materiel.

Also under development were chemical bombs of 100 pound size and incendiary bombs of 4, 40, and 100 pound sizes. Development in this field was later assumed by the Chemical Warfare Service.[20]

An anti‑tank mine was in the late stages of development.[21]

Fire control equipment available in June 1940 was apparently adequate for the direction of direct or indirect fire upon stationary targets, but required intensive development before it became suitable for use against aircraft or moving ground vehicles.[22]

Motor transport vehicles were the responsibility of the Quartermaster Corps until August 1942. The Ordnance Department, therefore, was not concerned with the development or standardization of these vehicles during the defense period.

The Effect of Climate and Terrain Upon Development Trends

The special climate and terrain problems posed by World War II were studied by the Ordnance Department as part of the continuing effort to develop weapons, ammunition and vehicles which would be efficient fighting gear regardless of the conditions under which they were used. The characteristics of jungle and cave warfare were examined in connection with the war in the Pacific. The difficulties faced by troops in desert and areas of extreme cold were studied for the purpose of aiding, primarily, the armies in Europe.

None of the studies undertaken, however, with the exception of those with regard to jungle warfare, were of particular value so far as World War II was concerned. Special attention was not given cave warfare until the spring of 1945, and the war ended before weapons especially designed for use against cave strongholds could be developed.

Fighting in the North African desert had ceased before the lessons learned from the testing of materiel in the California desert could be translated into weapons and vehicles for desert use.

Since little, if any, fighting was done at sub‑zero temperatures, the improvements indicated by cold weather testing in Canada proved of small value.

Special studies of climate and terrain, however, though not immediately valuable, provided data which would help, from a long‑range point of view, in the general improvement of materiel for which the Ordnance Department held procurement responsibility.

Jungle Warfare

Development of weapons especially suited for jungle use began in the summer of 1943. Ordnance along with other technical services was to determine weapons which would be effective in the destruction or diffusion of Japanese infantry in defensive lines consisting of individual soldiers in fox holes or prepared positions with overhead cover. It was necessary that the weapons recommended be readily transportable over jungle trails (60 pound maximum load) and susceptible to rapid manufacture.

Of the standard equipment available, Ordnance immediately recommended Hand Grenades Mk. II and Mk. IIIA2, Rifle Grenades M17 and M9A1, Bazooka, 37mm Gun M3A1, 60mm Mortar M2, 81mm Mortar M1, 75mm Howitzer M1A1, and 105mm Howitzer M3, plus the appropriate ammunition. The weight of the artillery pieces recommended, except the mortars, exceeded the weight limitations.

Ordnance also felt that three types of experimental mortar ammunition and the 4.5-inch rocket launcher under development would also be useful under the conditions described.[23]

The recommended weapons began tests against fox holes and simulated Japanese bunkers at Aberdeen Proving Ground on 6 September 1943.

Although discussions during the autumn of 1943 brought forth suggestions for the addition of such items as 105mm and 155mm mortars, 7.2-inch, 8-inch, and 10-inch rocket launchers, and an improvised self‑propelled 105mm howitzer based on a light tank chassis to the list of more important items to be especially produced for use in the Pacific, only the two mortars and a light submachine gun were actually added to the list originally proposed by the Ordnance Department.

The 81mm mortar and the 75mm and 105mm howitzers were removed from the list compiled in September.

Before the Jungle Warfare program was completed, Ordnance had provided sixty‑four special items—thirty types of ammunition, seven small arms items, five types of rockets and rocket launchers, eight artillery items, three automotive items, eleven types of bombs and other items desired by the Air Force.

The most important items were five different grenades (all for use with the rifle), the caliber .45 Submachine Gun M3, the Bazooka (2.36-inch) and 4.5-inch rocket launcher, the 37mm Gun T32, the 60mm Mortar T18, the 105mm Mortar T13, and the 155mm Mortar T25. None of the principal items furnished carried the same model numbers as those listed in September 1943. All weapons especially provided had undergone development.

The most advanced types of delay, super‑quick, and VT fuzes were also furnished for jungle use.[24] All but a few items pertaining to the Ordnance portion of the Jungle Warfare Project had been shipped by 1 July 1944.

Cave Warfare

Special attention was given to the problems engendered by the prospect of protracted cave warfare against the Japanese following a memorandum from the Commanding General Army Ground Forces to the Chief of Staff, describing the difficulties anticipated in fighting the Japanese on their home islands.[25]

The Director of the New Developments Division, WDGS, informed the Chief of Staff, 12 May 1945, that from an equipment standpoint the best means of meeting the anticipated conditions was to increase the amount of mobile firepower available in the Pacific. So far as Ordnance materiel was concerned, the Director felt this result could be achieved by immediately introducing into that theater 57mm and 75mm recoilless rifles, advanced types of rockets, 155mm self‑propelled guns, mortars of the 60mm, 105mm, and 155mm size, and other miscellaneous items.

As soon as possible, the Director hoped also to be able to ship the light tank mounting the 75mm gun, the medium tank mounting the 76mm gun, the heavy tank mounting the 90mm gun, the 90mm gun motor carriage, the 155mm howitzer motor carriage, and the dual 40mm gun motor carriage.[26]

Two days later, 14 May 1945, the Director called representatives of the technical services, including Ordnance, into conference to discuss the Cave Warfare Program and enlist their aid.[27]

In his first report on the subject of cave warfare, 21 May 1945, the Chief of Ordnance differed somewhat with the NDD Director as to the major weapons which would be most effective, proposing that only the 57mm and 75mm recoilless rifles, the 90mm and 155mm gun motor carriages, and the heavy tank mounting the 90mm gun be rushed to the Pacific. These five weapons were immediately available for shipment.[28]

Four days later, 25 May 1945, the chief of the Ordnance Research and Development Service called his division chiefs into conference, informed them what had gone before with respect to the Cave Warfare Program and enlisted their aid. He said he had “emphasize[d] to the War Department that we already have powerful weapons applicable to cave warfare which have never been used in the Pacific and [had urged] that these weapons, already in production in considerable quantity, be immediately made available to the fighting troops in the Pacific.”[29]

In addition to the five weapons suggested to the Director, NDD, the Ordnance R&D Chief told his principal assistants that the only other weapon he believed of immediate value was the 37mm Spigot Mortar, currently under development.

In a report of 28 May 1945, however, the Ordnance Department recommended that the 155mm howitzer motor carriage, the 105mm and 155mm mortars, and the multiple launcher for the 7.2-inch rocket be added to the list of weapons to be made immediately available to the Pacific Theater.

He also pointed out that Ordnance had under development other munitions which would probably be effective against caves. This materiel included a 105mm recoilless gun, a 250 pound rocket made from a 250 pound general purpose bomb and jet‑propelled, 105mm and 155mm mortars offering a range of 5,900 yards, a 250mm mortar, a 37mm spigot mortar, and an 8-inch rocket and launcher.[30]

During June 1945, the Ordnance Department also suggested that the conversion of the 155mm Gun Motor Carriage to an 8-inch gun motor carriage, the use of the light tank M24, and the use of the 75mm aircraft cannon mounted in B‑25 aircraft might be helpful in routing the Japanese from caves.[31]

The energy poured into the Cave Warfare Program was, of course, largely wasted since the Japanese capitulated 14 August 1945, before the effects of this intensified effort could be felt in the Pacific area.

Desert Warfare

Ordnance involvement in the domestic test program intended to improve the operational efficiency of vehicles used in desert fighting came in August 1942 when the Ordnance Department assumed, from the Quartermaster Corps, responsibility for the design and development (as well as procurement, supply, and maintenance) of motor transport vehicles.

The desert test program had been inaugurated in February 1942 at the verbal request of a representative of the Assistant Chief of Staff, G‑4, and was originally intended to determine the amount of traction needed by motor vehicles to permit them to operate successfully in desert areas and to determine the effect of sand on vehicle operation.[32] Planning for the November invasion of North Africa was apparently in progress.

The site chosen for desert training was the Imperial Valley of California, along the Mexican border about midway between San Diego and Yuma, Arizona. The military installation established there was designated Camp Seeley.

Following assumption of control of the Camp Seeley test program by the Ordnance Department, desert testing of tanks and other combat vehicles was also begun, the first tanks arriving in March 1945. It was originally intended, with respect to tanks, to restrict desert testing to the synthetic rubber used in bogie wheels and track assemblies. But, as was the case in all other projects inaugurated by the Ordnance Test Command at Camp Seeley, “one thing led to another until every ‘bug’ in the tank was under investigation.”[33] The testing of motor transport vehicles, with emphasis on rubber, fuels and lubricants, continued.

Desert testing continued at Camp Seeley until February 1944 when an Ordnance Department directive ordered the Desert Proving Ground closed.[34] Administrative control over Camp Seeley had been transferred from the Ninth Service Command to the Ordnance Department in July 1943.[35]

The desert test program, like the cave warfare project, was relatively ineffectual, because desert warfare had ended before the discoveries made at Camp Seeley could be incorporated in vehicles and used in the North African desert. The one major exception to the general lack of direct World War II value of desert testing was the development of low pressure tires which enabled transport trucks to traverse sand areas with greater ease than had been possible with conventional tires. This development occurred in the early months of 1942, while the Quartermaster Corps still held responsibility for the testing program at Camp Seeley. In the combat vehicle field, desert testing didn’t begin until March 1943. The fighting in North Africa ceased two months later.

The data gathered at Camp Seeley, however, had some value in that it gave transport vehicles and combat vehicle designers information with respect to the operation of trucks and tanks in high temperatures and heavy dust and suggested changes which improved the general performance of these vehicles.

Arctic Warfare

Although American forces were never required to conduct operations under Arctic conditions during World War II, the Ordnance Department, on the chance that such operations might sometime be necessary, tested ordnance in subzero temperatures during the winters of 1942‑43 and 1943‑44.

Three different locations were utilized, all in Canada. During the winter of 1942‑43, all types of materiel were tested at Shilo Camp, Manitoba. The following year fire control instruments for field artillery and anti‑aircraft artillery were tested at Fort Churchill, Manitoba, and combat and motor transport vehicles were operated along the Alcan highway between Dawson Creek, British Columbia and Whitehorse, Yukon Territory.

The Shilo Camp tests were authorized by Headquarters, Services of Supply, 10 October 1942,[36] although the site was not chosen until late in October, when the Canadian government agreed to use of Shilo Camp by the Ordnance Department in return for the privilege of training a Canadian parachute battalion at Ft. Benning, Georgia.[37]

Testing was conducted under the direction of personnel from Aberdeen Proving Ground, forty civilian engineers, chosen from commercial organizations which had manufactured the equipment tested, being invited to participate as observers and consultants.[38] The camp was located about 125 miles west of Winnipeg, 20 miles east of Brandon, Ontario, and about 75 miles north of the North Dakota border.

Between 1 December 1942, when the first group of test personnel left Aberdeen, and 1 March 1943, when Shilo Camp was evacuated, all types of ordnance—combat vehicles, motor transport vehicles, artillery, small arms, ammunition, bombs, fire control, fuels, lubricants, and tires—were tested in sub‑zero temperatures. In general, equipment performed satisfactorily in excessive cold although corrective action was indicated with regard to some items, because:

Weaknesses were discovered in cast homogeneous and face‑hardened armor plate, unionmelt weldments, and mild‑steel supports and brackets.

Excessive breech flash and muzzle flash were observed in some lots of carbine ammunition, mechanical time fuzes occasionally behaved erratically, 37mm canister ammunition misfired on occasion, some 155mm propellant powder exhibited excessive pressures, there were numerous fin failures in 60mm mortar ammunition, duds were numerous among anti‑tank grenades, and the Bazooka rocket occasionally hung fire or burned slowly.

The Browning automatic rifle tended to become sluggish, snow and frost increased the difficulty of elevating and traversing artillery, counter‑recoil action of artillery was slowed, 75mm and 105mm howitzers were sluggish, rifle bore cleaner was unsatisfactory below zero, emplacement of large artillery was difficult on frozen ground, and gun covers became stiff and unwieldy.

Bubbles in fire control levels became too large, the cement holding prisms in range finders cracked and prisms became loose, and anti‑aircraft gun directors and fire control generator units required auxiliary heating aids.

Existing cold‑starting aids for vehicles were not highly effective, coolants of a petroleum or calcium base or of alcohol were unsatisfactory, synthetic tires and tubes containing a neoprene base became brittle and afforded little traction, batteries lost capacity and could not be charged at low temperatures, summer lubricants congealed so rapidly that change to winter lubricants was difficult, plastics became brittle and broke easily, and drivers were not adequately protected from the cold.

Steel tank tracks offered inadequate traction when packed with snow, tank engine generator sets were unreliable, the idler on the medium tank collected ice and snow, and entrance hatches on tanks were not large enough to permit easy entry of personnel wearing bulky winter clothing.[39]

On the grounds that temperatures at Shilo Camp had not been low enough long enough to adequately test the sub‑zero operation of fire control instruments, the Fire Control Design Division of Frankford Arsenal requested of higher authority, in the summer of 1943, that it be allowed to send a detachment to Fort Churchill, Manitoba, for further tests of fire control.[40] The request was granted and one officer, thirteen enlisted men, and eleven Frankford civilian employees were ordered to Fort Churchill, a military post on Hudson Bay approximately 650 miles northeast of Shilo Camp, late in September 1943.[41]

The Fort Churchill tests, conducted between 15 October 1943 and 30 March 1944, not only bore out what had been discovered at Shilo Camp with respect to fire control, but also revealed that no type of available anti‑fogging solution would successfully remove the fog that settled on optical instruments when the warm breath of operators came in contact with them and that condensation of moisture on these instruments was a major problem when they were subjected to rapid changes in temperature. Most of the major fire control instruments tested were difficult to operate at sub‑zero temperatures, although most could be made operable by means of special operational procedures or minor adjustments.

Of the four models of generating units tested, only the M1 was found unsuitable for operation below zero. The M5 and M6 would perform satisfactorily in temperatures as low as minus 35 degrees (the lowest temperature encountered at Fort Churchill), although they required assistance in starting at minus 15 degrees. The M7 unit needed help in starting at plus 10 degrees.

Minor difficulties were discovered in the operation of each of the four models of directors tested, but nothing serious was encountered. The M5 and M5A1 models required special lubrication for successful operation at all temperatures. Although special oils and greases were necessary, all four remote control systems operated satisfactorily in sub‑zero weather.

Low temperatures apparently had no effect on the fuze setter rammer that could not be remedied in the field.

No major difficulty was encountered in connection with sighting instruments or optical instruments, although care had to be taken that moving parts were not over‑lubricated, that eye‑piece guards did not become filled with snow.

The Height Finder M1 operated successfully without the heated cover in temperatures as low as minus 30 degrees. The M2 model, however, was found to be almost entirely unsuited to Arctic use.[42]

Tests of vehicles along the Alcan highway were authorized by Army Service Forces (ASF) on the same date, 25 September 1943, that the Frankford Arsenal group was ordered to move to Fort Churchill.[43] Test personnel utilized the facilities created by the Corps of Engineers at Dawson Creek and the highway itself served as a testing area.

Primary purpose of the 1943‑44 vehicle tests was the improvement of winterization kits which had been developed as a result of experience at Shilo Camp the previous winter. Personnel from Office of the Chief of Ordnance, Detroit and Aberdeen Proving Ground, supervised the test program, which involved 100 combat and motor transport vehicles. These vehicles rolled up approximately 475,000 miles during the four months between 1 December 1943 and 31 March 1944. In addition to providing data concerning the adequacy of winterization kits, the test fleet also carried cargoes of supplies for the military installations between Dawson Creek and Whitehorse.[44]

The general conclusion reached at the end of the Dawson Creek tests was that winterization kits should be subdivided into a general kit and an Arctic attachment (principally a special engine heater). With this idea in mind, Ordnance suggested that the specifications for winterization kits should be amended to specify protection against temperatures of minus 15 degrees rather than minus 40 degrees as had previously been decided upon.[45] Both Army Service Forces and Headquarters, Army Ground Forces, disapproved the suggestion, thereby precipitating a series of discussions on the subject.

It was finally agreed that basic components of winterization aids be installed on vehicles as they were produced. The degree of protection this equipment was to provide was not stated. Also, equipment which would make it possible to start and operate vehicles at minus 40 degrees was to be provided in the form of auxiliary kits, sufficiently simplified to permit installation by third echelon maintenance personnel. This agreement, which gave some weight to Ordnance suggestions, was reached in October 1944.[46]

The Course of Development

Either directly or indirectly, all development projects pursued by the Ordnance Department were intended to increase either the firepower or mobility of the U.S. Army and the armies with which it was allied in World War II. The purpose of this section is to trace, in general terms, the trend of development in combat vehicles, transport vehicles, artillery, small arms, aircraft armament, artillery ammunition and bombs, small arms ammunition, rockets, and miscellaneous fields such as fuels, lubricants, rubber, and steel. Research in the ballistics field will also be discussed.

Combat Vehicles

Combat vehicles are those which mount armament and are primarily intended for offensive use. They include tanks (light, medium, and heavy), gun motor carriages (multiple, light, medium, and heavy), armored cars and scout cars.

Though they do not exactly fit the definition of combat vehicles, half‑track vehicles, track‑laying tractors, and tracked cargo carriers are generally considered such, because they work in close collaboration with true combat vehicles.

World War II tank development showed a consistent trend toward use of more powerful tank guns and thicker armor. Consequently, virtually all tanks tended to become heavier as development continued.

The 12‑ton Light Tank M2A4 of 1940 was followed in the same year by the M3 model which weighed 14 tons, because of an increase in the thickness of armor plate. The M5 model, standardized in November 1941, weighed 16 tons. The three early versions of the light tank mounted the 37mm gun as their principal weapon. A further effort to increase the striking power of the light tank ran into difficulties. A 57mm gun and finally a 75mm gun were incorporated into a proposed light tank in late 1941 and early 1942, but the increases in firepower necessitated such other changes that the final vehicle weighed 25 tons and was standardized in August 1942 as Medium Tank, M7.[47] The M5 light tank was superseded, a year before the end of the war, by the M24 model, which weighed 20 tons and carried a 75mm aircraft gun as its primary armament.[48]

A similar trend was noticeable with respect to medium tanks, the 20 ton M2A1 of 1940 with its 37mm gun giving way to the 31 ton M3 of 1941. The M3 carried a 75mm gun in the right sponson. A similar tank, containing a 75mm gun mounted in the turret, was designated M4 and standardized in September 1941.[49]

Since the M7 medium tank, originally intended as a light tank, held no appreciable advantage over the M4 model, it was never produced in quantity. The M4 tank continued as the standard medium tank throughout the remainder of the war, although it was modified by the addition of a 76mm gun to become known as M4 (76mm) and by the addition of a 105mm howitzer to become known as M4 (105mm howitzer) and M4A3 (105mm howitzer). These modifications raised the weight of the vehicle to approximately 35 tons.

Tanks of the T20 (experimental models are given the “T” designation) series were intended to fall into the medium tank field when development began in 1942, but became so heavy during the course of development that they were standardized as heavy tanks.[50]

There was no standard heavy tank in 1940, although development of such a vehicle got underway in the latter half of that year. The resulting tank, standardized in 1941 as Heavy Tank M6, weighed 60 tons and mounted a 3-inch gun as its principal weapon. Since neither the U.S. Army or allied armies at that time felt a need for a heavy tank, only forty were manufactured.[51]

The heavy tank came under development again in late 1944 when the T25 and T26 versions of the T20 series outgrew the medium tank family. The heavy tank standardized in May 1945 as M26 mounted a 90mm gun as compared with the 3-inch gun of the earlier M6, but reversed the trend toward increased weight. The M26 weighed 42 tons.[52]

The gun motor carriage was essentially a development of World War II. Although such vehicles had been built on an experimental basis by the Ordnance Department during the period between the first and second world wars, the combat arms had no need for them and none was ever standardized.

In early 1941, however, light gun motor carriages were created by mounting 37mm, 40mm, and 57mm guns on half‑tracks, trucks, and tank chassis.[53] The only one of the resultant vehicles to be standardized was the 37mm Gun Motor Carriage, M4, declared standard in December 1941.[54] A similar vehicle was given the designation Light Armored Car, M8, and standardized in June 1942.[55]

Since the smaller guns proved to be relatively ineffective against enemy armored vehicles, most of the development work with respect to light gun motor carriages was halted early in the war, although a gun motor carriage mounting twin 40mm guns on a light tank chassis, primarily for use against aircraft, was standardized in 1944.[56]

Development of gun motor carriages carrying heavier guns was undertaken by the Ordnance Department at about the same time lighter weapons were being tested, although development of at least one medium gun motor carriage, the 75mm type, was begun in 1940, before the institution of the light gun motor carriage program.[57]

Experiments with 76mm, 3-inch, 90mm, and 105mm howitzer types were begun later. The first gun motor carriage standardized was the 75mm M3, quantity production of which was authorized in November 1941.[58] Other members of the medium gun motor carriage family were standardized during the early months of 1942, the 3-inch M5 in January,[59] the 105mm howitzer M7 in April, the 75mm howitzer M8 in May,[60] and the 3-inch M10 and M10A1 in July and August.[61] The 3-inch M5 was never produced in quantity.

Following the rash of standardizations in 1942, no other vehicles were added to the list of authorized medium gun motor carriages until 1944. The 76mm M18 was declared standard in March 1944,[62] the 90mm M36 in June,[63] and an improved 105mm howitzer motor carriage, the M37, in November.[64]

The only heavy gun motor carriage under development at the time the U.S. entered World War II was the 155mm M12, approved for development in May 1941.[65] This vehicle, standardized in August 1942,[66] was the only heavy gun motor carriage utilized extensively in World War II, the 155mm Howitzer Motor Carriage M41, and the 155mm Gun Motor Carriage, M40, not being declared standard until May 1945.[67] The latter vehicle, which utilized components of the M4 medium tank, could also mount the 8-inch howitzer.

In addition to the gun motor carriages mentioned above, the Ordnance Department also developed a series of multiple gun motor carriages, most of which carried varying numbers of caliber .50 machine guns. Some, however, also mounted 20mm, 37mm, or 40mm guns as principal armament. The most important of these from a production standpoint were the M16 and M17 models, both of which mounted four caliber .50 machine guns.[68]

The armored car was not included in the Ordnance Book of Standards in 1940, having been removed in 1937 in favor of the scout car.[69] It re‑appeared in 1942, however, in the form of an adaptation of the 37mm gun motor carriage designated Light Armored Car, M8 (see above).

Many other versions of the armored car were the subject of experiment during the course of the war, but only two reached standardization. One, the Armored Utility Car, M20, standardized in May 1943, was an improved M8.[70] The other, known as the Armored Utility Vehicle, M39, was based on the 76mm Gun Motor Carriage, M18, and became standard in December 1944.[71]

Scout Car, M3A1, was a standard combat vehicle as of 30 June 1940 and, with minor modifications, remained so throughout the war. No other scout car was standardized.

While no half‑track vehicles were standard as of 30 June 1940, three—the personnel carrier M3, half‑track car M2, and the 81mm mortar carrier M4—were authorized for quantity procurement before the end of the year.[72]

Versions of the personnel carrier and half‑track car produced by the International Harvester Company were designated M5 and M9, respectively, in the summer of 1942, although they were essentially the M3 and M2 vehicles.[73] The earliest 81mm carrier was replaced in 1943 by a model, designated M21, which would permit more efficient use of the mortar.[74]

Although Ordnance produced several types of tractors, most of the development work in this field was lavished on high‑speed models. Low‑speed, commercial types were of primary interest to the Corps of Engineers, and responsibility for the development of tractors moving at less than 12 miles per hour was transferred to that technical service from the Ordnance Department in 1944.[75]

The first of the high‑speed tractors developed by the Ordnance Department was the 7 ton M2 intended primarily for the hauling of bombing planes and for other airfield uses. This vehicle was standardized in February 1941.[76]

The remaining high‑speed tractors—three in number—standardized during World War II were used for the towing of artillery. The 13 ton M5, standardized in October 1942, hauled the 105mm and 155mm howitzers and the 4.5-inch gun.[77] The 18 ton M4, standardized in August 1942, towed the 3-inch anti‑aircraft gun, 90mm anti‑aircraft gun, 155mm gun, 8-inch howitzer, and 240mm gun.[78] The largest of the four tractors, the 38 ton M6, was standardized in June 1943 and was designed to haul the 4.7-inch anti‑aircraft gun, 240mm howitzer, and 8-inch gun.[79]

Tracked cargo carriers were strictly a development of World War II. Three models of cargo carriers were standardized, two of which—the M28 and M30—were produced in but negligible quantities. The M29 (and an amphibious version designated M29C), however, was an important vehicle. Begun by the National Defense Research Committee in 1941 as a vehicle intended for operation over snow, the M29 standardized in September 1943 was about 10 feet long and 5 feet wide, had a cruising range of about 200 miles and a top speed of 25 miles per hour.[80]

Motor Transport Vehicles

Since the character of the Army’s World War II fleet of wheeled transport vehicles had been established prior to transfer of responsibility for design and development from the Quartermaster Corps to the Ordnance Department in August 1942, principal Ordnance activity in this field consisted of modification of existing vehicles to meet the needs of the troops who used the vehicles.

Near the end of the war Ordnance embarked upon what was unofficially known as the Heavy Truck and Transporter program and by V‑J Day was experimenting with such vehicles as 8 ton 8 × 8 (eight wheels and eight driving wheels), 12 ton 6 × 6, and 25 ton 6 × 6 trucks. None of these vehicles being developed under this program were standardized for use in World War II.[81]

Artillery

The trend of artillery development just before and during World War II was in the direction of larger and more powerful guns and guns for special purposes. With respect to field artillery, attention was centered on heavy guns and howitzers of 155mm, 240mm, and 8-inch sizes. Experiments were conducted with mortars of 105mm, 155mm, 10-inch, and 914mm size, though none above 81mm was standardized.

Special weapons for use against aircraft and use as tank armament also occupied attention. These special weapons, too, exhibited the trend toward increased size and power. Artillery for use in aircraft will be discussed in a later portion of this section. Substitute standard and limited standard items are not considered standard for the purpose of this discussion.

On the date arbitrarily used as the beginning of the defense period, 30 June 1940, the Ordnance Book of Standards contained thirteen artillery pieces (mortars included) which had been pronounced suitable for immediate procurement in event of need. These weapons included 75mm, 105mm, and 240mm howitzers; a 155mm field piece; 60mm and 81mm mortars; 37mm, 3-inch, 90mm, and 105mm anti‑aircraft guns; 37mm and 75mm anti‑tank guns; and a 37mm tank gun. Several other types of artillery were in the final phases of development.

Four additions were made to the list of standard field artillery between the time the defense period began and the time the U.S. became actively involved in the war. The 8-inch howitzer M1 was standardized in July 1940, the 155mm howitzer M1 in May 1941, the 4.5-inch gun M1 (a modification of a 4.7-inch gun to bring it into conformity with a similar British weapon) in May 1941, and an improved model of the 155mm gun M1, designated M1A1, in June 1941.[82]

There was no further standardization of field artillery weapons for nearly two years, until a special 105mm howitzer (M3) designed for transport by air was standardized in March 1943.

Within the following year three other weapons were also standardized—an improved 240mm howitzer (M1) in June 1943, a 75mm howitzer (M3) for use on the 75mm Howitzer Motor Carriage M8 in August 1943, and an 8-inch gun (M1) in January 1944.[83]

After standardization of the 8-inch gun there was another hiatus of 14 months until the 155mm gun M2 (featuring a breech ring which was an improvement over those used in the M1 and M1A1 models) and the 8-inch howitzer M2 (which also contained an improved breech ring) were authorized for quantity production in March 1945.[84]

Of the ten major field artillery items made standard after 30 June 1940, four (8-inch gun and howitzer, 155mm howitzer, and 4.5-inch gun) were new weapons, the other six representing changes or improvements to previously existing artillery pieces.

The standard mortars of 30 June 1940 were the ones with which World War II was fought, with the exception of the 2-inch mortar M3 (for use on medium tanks of the M4 series) standardized in August 1943.[85] Improved models of the basic 60mm and 81mm mortars were developed, but were standardized too late (August 1945) for use in World War II.[86]

With the emergence of the tank as a major factor in World War II military operations, it was imperative that the artillery with which tanks were armed be increased in power. The only tank gun standard on 30 June 1940, the 37mm M5, was obviously inadequate. This need for more powerful and effective tank armament resulted in development and eventual standardization of eleven new or improved tank guns of 37mm, 75mm, 76mm, 3-inch, 90mm and 105mm size.

An improved 37mm tank gun, the M6 was standardized in November 1940, and during the following eight months two types of 75mm guns, the M2 (an adaptation of an experimental anti‑aircraft gun) and M3, were approved for quantity production.[87]

As was true with respect to field artillery, tank guns were standardized in waves. It was eleven months after standardization of the 75mm M3 before the 3-inch M7, intended for use in the heavy tank M6, was standardized in June 1942. Three months later, in September 1942, the first 76mm tank gun (M1) was approved as standard.[88] The 76mm gun superseded the 75mm guns as the 75mm guns had superseded the 37mm. Eleven months again elapsed before the next wave of standardizations.

The 1943 crop of tank guns was led by an improved 76mm model, the M1A1, standardized in August 1943. A month later the first 90mm tank gun (M3), an adaptation of the 90mm anti‑aircraft gun M1, was standardized. In November 1943 tank armament of still larger caliber, a 105mm howitzer (M4), was standardized for use with the medium tank M4. During the same month a further improvement of the basic 76mm gun, model M1A2, was also approved.[89]

After another eleven month wait, the 75mm M6, for use in the new light tank M24, was standardized in October 1944. The magic period of eleven months again elapsed before an improved 75mm gun (M17) for use in the same tank was standardized in September 1945.[90]

Development in the anti‑aircraft field produced four guns which merited standardization. Two of these guns, the 40mm M1 (an Americanization of the Swedish Bofors design) and the 120mm M1, were new to the U.S. Army, while the other two were improvements on the standard 90mm M1 of 1940. Two, the 40mm M1 and the 90mm M1A1, were standardized within a month during April and May of 1941. The 90mm M2 was standardized in May 1943, the 120mm M1 in January 1944.[91]

In addition to the two standard anti‑tank weapons of 30 June 1940, the Ordnance Department developed two others during World War II. One, the 3-inch M5, was new, while the other, the 37mm M3A1, was a modification of the existing 37mm M3. The 3-inch type was standardized in December 1941, the re‑designated 37mm type in March 1942.[92]

Small Arms

Probably the most spectacular World War II developments in the small arms field were those in connection with rocket launchers and recoilless rifles, although attention was given to the further improvement of the machine guns, submachine guns, rifles, and pistols standard in 1940.

The four machine guns designed for ground use (machine guns for use in aircraft will be considered in a subsequent discussion of aircraft armament), Browning caliber .30 M1917A1, Browning caliber .30 M2, Browning caliber .30 M1919A4, and Browning caliber .50 M2 remained in use throughout the war. Although these weapons were modified during the war, no new models were standardized.

Tests of seven types of commercial submachine guns between October 1939 and January 1942 convinced the Ordnance Department that the standard Thompson M1928A1 could be improved upon. By use of the information gained in these tests, the M1 model (which equaled the M1928A1 in performance and was nearly two pounds lighter) was developed in early 1942 and standardized in April 1942.

Even as the M1 submachine gun was being perfected, work was going forward on another model which promised to eliminate much of the “climb” experienced with both the M1928A1 and M1. Development of this second new model proceeded so rapidly that it also was standardized in April 1942, actually a few days before its nominal predecessor, the M1, was approved for quantity production.

A third refinement in the submachine gun field resulted in a weapon in the nature of a machine pistol which would fire either caliber .45 or 9mm ammunition. This new development was designated submachine gun M3 in December 1942 and superseded both the M1 and M2 models.[93]

The only World War II addition to the group of shoulder weapons (excluding submachine guns) provided the U.S. Army by the Ordnance Department was the caliber .30 carbine M1, a light weapon designed for personal defense.

With respect to other shoulder weapons, attention was centered on the improvement of the three rifles standard in 1940. Prior to August 1940 the Ordnance Department objected to development of a carbine on the grounds that ammunition supply would be greatly complicated by standardization of a fourth shoulder weapon. In August 1940, however, the Ordnance Department was ordered to proceed with development and responded by asking inventors to submit models for test. The carbine presented by the Winchester Repeating Arms Company was chosen and standardized as Carbine, Caliber .30, M1, in October 1941.[94]

A special type of carbine for the use of parachute troops was standardized as M1A1 in May 1942,[95] but no major changes were made to this weapon for the duration of the war.

No hand weapon other than the caliber. .45 pistol M1911A1 standard in 1940 was made standard during the war.[96]

Rocket launchers and recoilless rifles, though developed during World War II, utilized known principles, since the rocket had been used for military purposes as far back as the War of 1812 and rudimentary types of recoilless rifles had been the subject of experimentation during World War I.[97]

Development of the 2.36 rocket launcher (Bazooka) began in late 1941 as part of a project to increase the power of rifle grenades. The grenades tested proved to engender such a recoil movement that they could not be used with conventional shoulder weapons. The grenade, therefore, was converted to a rocket and a launcher was developed. This weapon was standardized in August 1942 as Launcher, 2.36-inch Rocket, Anti‑tank, M1.[98] A shorter version of the Bazooka was designated model M9 and standardized sixteen months later.[99]

A lighter Bazooka, made largely of aluminum, was also developed by the Ordnance Department, though not standardized in time to have appreciable effect on the outcome of World War II. Quantity procurement of the M18 launcher was authorized in April 1945.[100] A launcher, the M20, designed to utilize a 3.5-inch rocket, was standardized after the end of the war.[101]

Though the Ordnance Department felt, as late as December 1941, that there was no place for a recoilless rifle in the American arsenal,[102] experience with development of the rocket launcher raised the possibility that a usable recoilless rifle might be created. Frankford Arsenal was asked to determine ballistic data for such a weapon in June 1943. It was decided to use a 57mm tube for this gun, and a two and three‑quarter pound projectile. The first pilot was built and tested in October 1943,[103] although the completed weapon, designated Rifle, 57mm, M18, was not standardized until April 1945.[104]

Development of the second recoilless rifle standardized during the war, one of 75mm size, began in March 1944, at the request of Headquarters, Army Service Forces.[105] The pilot model was completed in September 1944 and the weapon was standardized, under the designation, M20, in July 1945.[106]

Aircraft Armament

At the beginning of the defense period, 30 June 1940, the Ordnance Book of Standards listed six weapons deemed satisfactory for the arming of aircraft. In addition to three machine guns—the Browning caliber .30 M1919A4, the Browning caliber .30 M2, and the Browning caliber .50 M2—which could be mounted on planes, two types of 20mm aircraft cannon, designated M1 and AN‑M2 (the “AN” prefix denoted joint Army‑Navy use), and the 37mm M4 were also available.

A new caliber .50 aircraft machine gun, the M3, was standardized in June 1945.[107]

Development of a 75mm aircraft gun began in 1938[108] and culminated in standardization of the M4 gun in October 1942.[109] This weapon was essentially an adaptation of the standard M3 tank gun. Subsequent development produced a 75mm aircraft gun of lighter weight and improved performance standardized as M5 in March 1944. A change in the rifling of the M5 gun to permit its use in planes capable of speeds in excess of 250 miles per hour resulted in a modification designated M5A1, standardized in November 1944.[110] Another version of the 75mm aircraft gun, differing from the M5A1 only in that it carried an improved feed mechanism, was standardized in October 1944 and given an M10 model number.[111]

The first wartime development with respect to 37mm aircraft guns was the adaptation of the M1A2 37mm anti‑aircraft gun to aircraft use. This adaptation was accomplished in 1942 and the resulting 37mm aircraft gun M9 was made standard in January 1943.

The 37mm aircraft gun M10, standardized 4 May 1944, was basically the standard M4 gun, with the addition of a disintegrating belt link which permitted planes using such guns to carry as many as 28 additional rounds of ammunition.

A modification decreasing the diameter of the M9 gun tube to permit easier mounting in planes was designated AN‑M9A1 and standardized in October 1944.[112]

Twenty millimeter automatic aircraft guns M1 and AN‑M2 were the only standard 20mm aircraft cannon during all but the last week of the war. The 20mm M3, a greatly improved weapon on many counts, was standardized in August 1945.[113]

To supplement the conventional types of aircraft armament and provide aircraft with a weapon akin to the infantry’s Bazooka, development of launchers which would permit firing of 4.5-inch rockets from planes was begun in 1942. After much experimentation, three‑tube clusters fabricated from a plastic composition was deemed adequate and standardized as Launcher, Rocket, 3‑Tube, 4.5-inch A.C., M10, in April 1944. A similar launcher built of magnesium was standardized as the M15 model in August 1944.[114] Training launchers of steel construction were also developed.

Artillery Ammunition and Bombs

It is obvious that, to be effective, artillery must have ammunition and bombardment aircraft must have bombs. Much of the World War II development work in the artillery ammunition field, therefore, consisted of that necessary to provide satisfactory rounds for newly developed weapons and special bombs for special purposes. At the same time, attempts were being made to develop improved explosives, improved propellants, improved fuzes, and improved projectiles in order to increase the lethal quality of ammunition and bombs.

Probably the most revolutionary wartime development in the ammunition field was the VT fuze, a device using electronic principles which made it possible to detonate artillery shells or bombs at a desired distance from the target.

Actual development of the VT fuze (nine different fuzes, each with a special purpose, had been standardized by the end of the war) was accomplished by Division Four, National Defense Research Committee, in cooperation with the Navy and the Army’s Ordnance Department.[115]

One of the best means of raising the destruction potential of ammunition is to increase the power of the explosive used. To reach this desired end, the Ordnance Department experimented with new explosives and combinations of known explosives throughout the war. The most important of these “new” explosives was RDX, widely used for the first time as a military explosive in World War II, although it had been patented as a medicine in Germany in 1899 and as an explosive in Great Britain in 1920 and in the U.S. in 1922. Sixty‑two percent more powerful than TNT, it was not often made during the peace years because its manufacture required the use of expensive methyl alcohol and because eleven pounds of nitric acid were required to produce one pound of RDX.

This powerful explosive was seldom used in the pure state, but formed the basis for other widely used compounds. Composition A, composed of RDX and beeswax (a desensitizing agent) went into the boosters or bursting charges of various rounds of ammunition. Composition B, a mixture of RDX and TNT, was used for filling bombs. Composition C (and improvements designated C2 and C3) comprised mixtures of RDX and oils or other materials and was used for demolition purposes. A fourth important explosive utilizing RDX was Torpex, a compound of RDX, TNT, and aluminum, generally used when underwater explosions were required.[116]

Other World War II developments which were put to widespread use during the war were Tritonal (TNT-aluminum mixture also used by the Germans and Japanese), Tetrytol (TNT-tetryl combination of particular value in the shaped charges, described below), Pentolite (PETN-TNT mixture used in a wide variety of burster charges)[117] and Picratol (TNT-ammonium nitrate combination used in bombs).[118]

The PETN used in the creation of Pentolite is classed as a World War II development, although the chemical process was patented in Germany in 1894 and had been used in this country since 1937.[119] Amatol, a mixture of TNT and ammonium nitrate devised in World War I, was utilized in artillery ammunition during the early stages of World War II, but was abandoned when TNT became plentiful.[120]

EDNA (or Haleite, after the name of the Picatinny Arsenal chemist who developed it) was the only previously unknown explosive perfected during World War II. Forty percent more powerful than TNT, EDNA was standardized in July 1943,[121] but was not extensively used because a large capacity for the production of TNT had been created and EDNA was not a sufficient advance over TNT to justify converting TNT plants to EDNA production. An EDNA‑TNT combination, named Ednatol, proved satisfactory for the loading of bombs, but did not replace other explosives.[122]

Other developments in the ammunition field also showed the tendency toward increased efficiency in operation and increased lethality. Fuzes which would pierce concrete, base‑detonating fuzes which improved armor‑piercing projectiles, and better fuze‑timing mechanisms were developed.

Armor‑piercing shot was made more deadly by incorporation of a tungsten carbide core. A new type of filler for grenades increased the number of fragments hurled upon explosion. Anti‑tank and anti‑personnel mines became more powerful and simpler to operate as the war progressed.

Four thousand pound “block buster” bombs were developed as were other bombs of smaller size. Developments designed to improve the performance of bombs included cluster adapters which would permit simultaneous release of large numbers of small bombs, parachutes which retarded the fall of a bomb sufficiently to allow for a low‑flying plane to escape the effects of detonation, and anti‑ricochet attachments to prevent bombs from bouncing harmlessly away from targets.

New primers and propellants calculated to reduce the flash and smoke given off by artillery were tried. Capitalizing on the remarkable armor‑piercing capability of ammunition containing a cavity within the explosive charge, the Ordnance Department lined the inner cavity with metal and discovered that the high‑velocity jet of metallic particles which derived from the cavity lining materially increased the potency of Bazooka rockets and artillery ammunition. This modern application of an old principle resulted in what became known as the “shaped charge.”[123]

Small Arms Ammunition

At the end of World War II the list of standard small arms ammunition had shown an appreciable increase in length over the list of 30 June 1940.

The most important of the new rounds were the caliber .30 and caliber .50 incendiaries, the caliber .50 armor‑piercing incendiary, and the caliber .50 armor­piercing incendiary tracer. Many existing rounds, in addition, underwent at least one modification during the war.

The two new incendiaries were standardized in September 1941, the caliber .50 API in October 1943, the caliber .50 APIT in April 1945.[124]

Two improved types of caliber. .45 shot (as opposed to ball) cartridges were developed during the war, one being standardized in October 1943, the other in December 1943.[125]

Two early wartime developments with respect to caliber .50 ammunition were the armor‑piercing round M2 and the ball cartridge M2, both standardized in February 1941. Development of a caliber .50 tracer apparently occupied much attention, because four different types were standardized during the course of the war. The first wartime caliber .50 tracer development was designated M2 and standardized in January 1942. The M2 was replaced by the M10 model in October 1943 and the M10 was in turn replaced by the M17 in August 1944.

The final wartime development was the “headlight tracer” M21 of April 1945. The latter round was designed to wreak psychological havoc on the enemy by allowing him, as well as the person firing the round, to see the fiery trail of the tracer.[126]

A basic round for the new caliber .30 carbine was standardized in September 1941, and a tracer for use in this weapon was standardized in January 1944.[127]

To make possible the firing of grenades from shoulder arms, a new rifle grenade cartridge was made standard in September 1941, a carbine grenade cartridge was released for quantity procurement in February 1943 and an auxiliary grenade cartridge was standardized eleven months later.[128]

A tracer for use in caliber .30 weapons was standardized in January 1942.[129]

Rockets

From virtually a standing start in 1940, the Ordnance Department accomplished standardization of two types of 2.36-inch (Bazooka) rockets and two types of 4.5-inch rockets during World War II. In addition to these four combat rockets, the standardization stage was also reached with respect to a 3.25-inch rocket used as a target for anti‑aircraft fire and practice rockets of 2.36-inch and 4.5-inch size. The two 7.2-inch rockets standardized did not assume that status until December 1945.

American military rocket development for World War II began in 1941 when the Ordnance Department began considering the possibility of adapting British anti‑aircraft rockets to U.S. Army use.[130] The resulting 3.25-inch anti‑aircraft rocket was procured to a limited extent, but the more accurate anti‑aircraft artillery was being developed so rapidly that there was no need for an anti‑aircraft rocket.

A further adaptation of the British rocket, however, proved of value in training anti‑aircraft crews to place their fire on a moving object and was standardized in April 1942 as 3.25-inch training rocket M2.[131] A modification designed to permit use of the target rocket at night was designated M2A1 and standardized in November 1944.[132]

The first standard Bazooka rocket was the M6, standardized in June 1942. At the same time, a practice version of the M6, designated M7, was also standardized.[133] The standard Bazooka rocket underwent numerous transmutations (A1, A2, A3, etc.) but the basic design continued in use throughout the war, although a rocket containing white phosphorous smoke was standardized as M10 in September 1944.[134]

A 4.5-inch infantry rocket was not standardized until April 1945, but more than a million rounds of experimental types were produced. The first usable 4.5-inch rocket, designated M8, was never standardized. “Limited” procurement (procurement authorized prior to standardization), however, had resulted in production of more than 1,300,000 M8 rockets by the end of 1944.[135]

The first 4.5-inch rocket standardized was a “spin‑stabilized” model, M16, approved by Army Service Forces, in April 1945.[136] Tests of experimental rockets had revealed that rockets stabilized by rotational movement (spin‑stabilized) were more accurate than the earlier fin‑stabilized models (such as the M8). The M16 was designed for use in multiple launchers, while a similar rocket, designed for use in single expendable launchers, was standardized in May 1945 as the M20.[137] Practice rockets to complement each of the standard combat types were standardized as M17 and M21 respectively.

Making use of the work done by the Navy and the National Defense Research Committee in the development of a standard 7.2-inch Navy rocket, the Ordnance Department devised 7.2-inch rockets it felt might be put to use by the Army.[138] Development in this field was not completed in time for 7.2-inch rockets to be put to other than trial use in World War II. Two such rockets (one carrying CG gas, the other CK gas) were standardized in December 1945.[139]

The increase in the size of rockets made it imperative that the Ordnance Department master the manufacture of solventless double base propellant powder, since powder grains of a size required in large rockets could not be made by the solvent process originally used in the manufacture of rocket powder. By early 1944 solventless powder was being produced in sufficient quantity in the U.S. to permit almost complete replacement in the solvent type in rocket loading.[140]

Launchers were needed, of course, in order that rockets might be fired. Launchers, therefore, were developed concurrently with rockets. The Bazooka and aircraft launchers have been discussed above. To fire the 3.25-inch target rocket, a launcher named a “target projector” was standardized in April 1942. The first standard launcher for the 4.5-inch ground rocket was a plastic model, M12, approved for quantity procurement in April 1944. This launcher, modified to fit the M20 rocket, was designated M12A1 in November of the same year. The M12 series of launchers was expendable, the M12A1 launcher, and the M20 rocket being manufactured as a unit. No multiple launcher for the 4.5-inch rocket was ever standardized, although experimental types were tested.

The opposite was true with respect to 7.2-inch rockets. Two multiple launchers were standardized, but no individual launchers. The M17 multiple launcher contained twenty launching rails mounted on the M4 series of medium tanks. It was standardized in August 1944. The M24 multiple launcher, standardized after the war, contained twenty-four launching rails.[141]

Fuels and Lubricants, Rubber, and Steel

Before World War II the Army’s needs for fuels and lubricants and for rubber could be met by procurement through normal commercial channels. Research into steels was conducted by manufacturing arsenals of the Ordnance Department during the peace years, but appropriations were so small that similarly small progress was made. The threat, and later actuality, of war made necessary the intensification of research and development with respect to these important materials.

Since great quantities of fuels and lubricants were consumed by automotive vehicles, it was natural that the Ordnance Department should lavish most of its attention in this field on these vehicles. How to simplify the supply problem by reducing the number of fuels and lubricants procured while at the same time assuring satisfactory performance of equipment was the primary question faced by the Ordnance Department.

In 1940, the Army’s vehicles used 91‑octane aviation gasoline, 80‑octane motor gasoline, and 72‑octane motor gasoline. If the Army ever moved away from the handy gasoline pumps of the continental U.S., a tremendous supply task would be created.

The first step taken by the Ordnance Department to lessen the size of the supply problem was the redesign of the engine of the medium tank to permit operation on 80‑octane gasoline instead of the 91‑octane aviation fuel originally prescribed. Since vehicles which normally used 72‑octane gasoline would generally give even better performance on 80‑octane fuel, 80‑octane gasoline was chosen, in 1941, as the single standard combat fuel.[142]

Although 80‑octane gasoline had been decided upon as the standard combat fuel, a problem still remained, since this gasoline was furnished in three volatility grades to coincide with the commercial practice of adapting gasoline to the season of the year and the section of the country in which it was to be used. Additional experiments were made in an attempt to determine a single type of gasoline which would not cause vapor lock at high temperatures and which would start quickly at low temperatures. No such fuel was ever discovered although a gasoline (All Purpose Grade A) which would operate efficiently at temperatures ranging from zero to the highest encountered was produced after the results of cold‑room testing and experience at Camp Seeley, California, and Shilo Camp, Manitoba, had been analyzed. A second, and little used, gasoline (Arctic Grade C) was specified for use in vehicles operating at temperatures under zero.[143]

A diesel fuel of 50 octane number was standardized by both the Army and Navy in 1940 in order to simplify, as in the case of gasoline, the supply problem. Ultimately, however, the demand for this fuel became so heavy that it exceeded supply, and attention was given to the development of lower octane number fuels for Army use. Again, the testing facilities of Camp Seeley and Shilo Camp were utilized, the tests proving that fuels of octane count as low was 35 could be successfully used in Ordnance vehicles.[144]

There was a similar trend toward simplification and improved performance with respect to motor oils. In 1940 ten different types of motor lubricants were being used, five consisting of mineral oil and five of heavy‑duty oils (SAE viscosity grades 10, 20, 30, 40, 50 in each type). By the end of the year the number of authorized motor oils had been reduced to five (mineral oils of 10, 30, and 50 grades and heavy duty oils of grades 10 and 30). It was later discovered that the prescribed mineral oils would not give satisfactory performance under hard military usage, so near the end of 1942 it was decided that only heavy‑duty oils of 10, 30 and 50 weight would be used in the engines of military vehicles.

Still later it became necessary to rewrite the specifications for motor oils to permit the use of more easily obtainable additives in the refining of these motor oils. Tests of oils containing the less critical additives proved them satisfactory for military use.[145]

Other important wartime developments in the fuels and lubricants field included a recoil oil which would allow the operation of artillery recoil mechanisms in any weather, a preservative oil which would not only protect aircraft guns from rust but also permitted operation of the weapons at temperatures as low as minus 70 degrees, and a preservative oil which protected engine interiors from rust during shipment and storage.[146]

Rubber, from the Ordnance point of view, meant primarily truck tires and tank tracks, though rubber also had other uses in connection with materiel produced by the Ordnance Department. Long before World War II it was painfully apparent that war in the Pacific would probably eliminate the plantations of the Dutch East Indies, the Malay peninsula, and possibly Ceylon as sources of crude rubber. A stockpile of crude rubber, therefore, was accumulated in the U.S. during the period immediately preceding involvement of the U.S. in the shooting war. Despite the stockpile, however, it was obvious that the use of natural rubber would have to be strictly controlled and that steps must be taken immediately to convert, wherever possible, to the use of synthetic rubber. The construction of facilities for the production of synthetic rubber was rushed when war began.

Ordnance reaction to the rubber shortage took the form of:

substitution of reclaimed rubber for crude rubber to the extent possible;

elimination of, or substitution of other materials for rubber in relatively less vital components of major items;

development of steel tank tracks;

insistence that worn military tires, formerly salvaged, be re‑treaded and put to further use, and

development of synthetic tires, tubes, tank tracks and tank bogies.[147]

Throughout the war, the major Ordnance activity in the rubber field consisted of attempts to develop satisfactory tires and other products which contained increasing percentages of synthetic tires. Ordnance itself had no facilities for the development of rubber, making it imperative that virtually all experimentation with rubber be conducted by commercial organizations experienced in the manufacture of rubber products.

Ordnance gave direction to the development program and provided the vehicles and many of the other facilities used for testing new developments. Testing facilities were of considerable importance in the development of synthetic rubber, since so little was known of synthetics that development normally proceeded by means of analysis of the results of actual use of products manufactured from new synthetic mixtures. Little testing by theoretical methods was possible.

The characteristics of synthetic rubber began to form a pattern as the war progressed. Small tires built entirely of synthetics proved capable of performance equivalent to those manufactured of natural rubber, while, in general, the larger the size of the tire the smaller the percentage of synthetic rubber which could safely be used. Most truck tires, by the end of the war, contained 90% synthetic rubber, while only the very large artillery tires and combat tires contained lesser amounts.

Tank tracks and bogie tires proved more difficult to convert to synthetic rubber, the use of only an average of about 65% synthetic proving possible. The conversion of other items was almost complete.[148]

As the Army’s largest user of steel, the Ordnance Department was naturally interested in doing what it could to improve the quality of the steel going into Ordnance equipment. Watertown Arsenal, Watertown, Massachusetts, held the responsibility for research and development in steel. Since gun tubes and other Ordnance items experience greater stresses than do normal commercial products fabricated of steel, the Ordnance Department of necessity conducted more basic research in this field than it did in other fields in which commercial organizations had a more vital interest.

Between World Wars I and II, Watertown studied such basic metallurgical subjects as the effect of sulfur and phosphorous on the physical properties of steel, the behavior of steel under extreme stresses suddenly applied, and the fine details of the internal structure of various types of steel. Among the problems in applied research studied during the inter‑bellum period were the cold working of steel, the use of radiography in the inspection of steel, the centrifugal casting of gun tubes, and the development of homogeneous armor plate.

During World War II, Watertown continued its investigation of the properties of steels and application of its discoveries to specific Ordnance development problems. Basic wartime studies included research into the distribution of stresses in the steel of gun carriages and other materiel, the character of plastic flow in steel used for munitions, the nature of gun tube erosion, and the metallurgy of arc welding. Applied research dealt primarily with the composition of armor and the welding of such armor.

Studies of armor itself included investigation of the mechanism of armor penetration, the possibilities of light alloy steels (those using aluminum or magnesium) as aircraft armor, the correction of brittleness encountered with steels of low alloy content, the improvement of the metallurgical structure of heavy armor.

As regards the welding of armor, Watertown conducted continued experiments designed to make sure that armor, after welding, was as strong as it had been before welding.

In addition, Watertown conducted inquiries into the metallurgy of armor‑piercing projectiles and products manufactured from powdered metal, as well as developing graded standards of soundness for steel castings and qualification tests for welding electrodes.[149]

Ballistics

Ballistics, according to Webster, is “the science or art of hurling missile weapons by the use of an engine; the science of the motion of projectiles.” As far as the U.S. Army is concerned, this “art” is practiced solely by the Ordnance Department.

Practice of the science requires the use of three better‑known sciences—physics, chemistry, and mathematics. The fountainhead of knowledge in this field is the Ballistics Research Laboratory at Aberdeen Proving Ground, Maryland.

For purposes of research, ballistics is divided into three categories—interior (study of the phenomena surrounding the institution of motion in the projectile), exterior (study of the forces affecting the behavior of an airborne projectile), and terminal (study of the effect of the projectile at the target).

Discoveries in the field of ballistics largely determine the design of guns, the size and shape of ammunition and bombs and their components, and the types of explosives to be used.

For example, the Ballistics Research Laboratory assisted in the development, during World War II, of more than seventy types of projectiles and the new models of 75mm, 76mm, 90mm, 105mm, and 240mm guns. It also determined the optimum dimensions for guns ranging in size from 57mm to 914mm. Much of this data was not used during the war, but was filed for use in future development. Fragmentation effect studies of the Ballistics Research Laboratory were used in determining the most effective distance from the target for detonation of artillery projectiles using the VT fuze.

Chronograph equipment capable of being used in the field to determine the ballistic adequacy of artillery and artillery ammunition was developed at the Ballistics Research Laboratory and used in overseas theaters. Bombing tables for every standard bomb and firing tables for every standard item of artillery ammunition and every rocket were computed by the Ordnance Department.[150]

To permit the study of ballistics to proceed with more exactitude and more speed, the Ordnance Department sponsored, during the war, construction of a supersonic wind tunnel, an aerodynamic spark range, and two advanced computing devices—the ENIAC (Electronic Numerical Integrator and Calculator) and EDVAC (Electronic Discrete Variable Calculator). Though but one of these projects was completed in time to be of appreciable value in World War II, their value in future development is undoubted.

Ordnance suggested to the Office of Scientific Research and Development in February 1942, the advisability of constructing a supersonic wind tunnel, although it didn’t agree with the OSRD suggestion that such a tunnel should be located at Aberdeen.[151] The OSRD view prevailed, however, and in May 1942 the Ordnance Department requested SOS approval of the expenditure of $700,000 for erection of a supersonic wind tunnel at Aberdeen. The request was temporarily disapproved on the grounds that sufficient construction material could not be made available.[152] Approval was later granted, however, and construction of the tunnel began early in 1943. The first model bombs were tested in the tunnel in January 1945.[153]

The supersonic wind tunnel permitted the testing of bombs, projectiles, and other types of missiles in air stream velocities of Mach numbers (the ratio of air stream velocity to the velocity of sound) 0.1 to 0.9 and 1.3, 1.7, and 4. The tunnel could not be used to test missiles at velocities in the neighborhood of the velocity of sound, making it necessary that an aerodynamic spark range be provided for study of missiles at velocities between Mach numbers 0.9 and 1.1.[154]

The aerodynamic spark range designed to cover the blind spot in the supersonic wind tunnel was completed late in 1943[155] and put to considerable use during World War II. It differed from the wind tunnel in that model projectiles, instead of being held stationary, were fired down a darkened range and photographed, at nineteen stations, in the illumination provided by a spark of high intensity and a duration of about 1/100,000 second. From the photographs, the drag of the projectile, its deceleration, orientation in space, yaw, mutations, and various other phenomena could be inferred.[156]

ENIAC was begun by the Moore School of Engineering of the University of Pennsylvania in 1943, after it had become apparent that the Bush Differential Analyzer and the International Business Machines equipment being used at the Ballistics Research Laboratory could not adequately handle the computations necessary to ballistics research. ENIAC was the most intricate and complex electronic device in the world, requiring for its operation 18,000 electronic tubes. A ballistics problem which, during the war required twenty‑five man‑months of the time of an experienced computer, could be answered by ENIAC in two hours.[157] ENIAC was installed at Aberdeen in early 1946.

During the development of ENIAC, the necessity for a computer with a greater capacity for storing numbers became apparent. Therefore, in July 1944, the Moore School began the design of such a machine, christened EDVAC. This computer had an internal memory capacity for about 2,000 ten‑digit decimal numbers, while ENIAC accommodated only twenty.

Also, in order to change from one type of problem to another, it was necessary to prepare the ENIAC by setting numerous switches and plugging in many interconnecting cables. EDVAC was set automatically for each new problem.[158] Only the initial phases of development of the EDVAC had been completed by the end of the war.

The completion of ENIAC and EDVAC tended to make the Ballistics Research Laboratory independent of human computers and to open new fields of research, particularly with respect to nuclear physics and the aerodynamics of guided missiles, which previously had been closed because of insuperable computational obstacles.[159]

Unfinished Business, 1945

Before the end of World War II, the Ordnance Department examined its research and development program and decided which of the 880 development projects active on V‑E Day should be continued beyond V‑J Day.

In general, it was decided that development which represented expedients designed to meet special tactical situations should be dropped. Others, which might be expected to prove helpful in the general improvement of ordnance, were to be continued. The number of active projects was cut, after V‑J Day, to 675.[160]

The Ordnance Research and Development Service, in June 1945, listed six major research projects which should be continued after the war. Four of these had to do with guided missiles. The basic guided missile project, given the code name of ORDCIT, was underway at California Institute of Technology.

A supplementary project, HERMES, involved the General Electric Company and looked forward to the development of ground‑to‑air missiles for use against targets traveling at supersonic speeds. The German “V” weapons were to be used as the point of departure in this field.

The NIKE project, utilizing the facilities of the Bell Telephone Laboratories, was to develop similar missiles for use against targets traveling at subsonic speeds.

In order that the guided missiles developed might be tested, a fourth project called for the necessary construction at a proving site in New Mexico (subsequently dubbed White Sands Proving Ground).

Massachusetts Institute of Technology was engaged in a theoretical study of bombs, fuzes, and accessories which was to lead, if necessary, to a complete redesign of the bombs and fuzes carried by bombers of increased speed, flying at higher altitudes and consequently experiencing lower temperatures. Research and Development Service felt this study should continue.

The sixth major project involved four of the most important rubber companies—U.S. Rubber, Goodyear, Goodrich, and Firestone—and called for development of improved military tires, tubes, flaps, and bead locks.[161]

In addition to the major projects, a postwar development program for other types of Ordnance equipment was also formulated.

The possible use of aluminum in helmets, body armor, cartridge cases, and machine gun mounts was felt to be worthy of postwar study in the small arms field.

Continued attempts were to be made, too, to develop a catapult device for the ejection of the pilot from jet‑propelled aircraft, to improve the performance of the bazooka, to develop satisfactory 37mm and 105mm recoilless rifles, to complete the development of the caliber .60 machine gun and a seven‑pound infantry rifle.

With respect to aircraft armament, postwar attention was to be devoted to further improvement of the 20mm, 37mm, and 75mm aircraft guns and development of paracrates (crates with attached parachutes) which could be aimed.[162]

Postwar emphasis in the motor transport field was to be placed on heavy tank transporters and various types of special purpose vehicles.[163] The Ordnance Department felt that development of heavy tanks of the T29, T30, T32, and T34 types should be continued after V‑J Day, as should development of various types of tractors.

In addition, it was believed that continuing efforts should be made to improve the performance of combat vehicle components, such as engines, transmissions, bogies, and differentials. It was anticipated that improved carriages for self‑propelled artillery would be required.[164]

A broad program of artillery research and development was planned for the postwar period. In general, attempts were to be made to increase artillery firepower, to develop lighter, smaller, more accurate guns of increased mobility. It was believed that the towed artillery carriage and existing types of anti‑aircraft guns were virtually obsolete.

Basic research was to include studies of the dynamics of the structure of gun carriages, exploration of possible new methods of absorbing recoil energy, a general study of gun tubes erosion, examination of the stresses and temperatures experienced by the inner face of gun tubes during firing, continued study of the physical characteristics of gun tube forgings, further investigation of the changes occurring in steel during the cold‑working of gun tubes, examination of the possibility of using high‑strength steels and light metal alloys in gun tubes.

Development of rapid‑fire 75mm and 3-inch anti‑aircraft guns, tank guns of 90mm, 105mm, 120mm, and 155mm size, a 3-inch field gun, and 81mm, 105mm, and 250mm mortars was to continue. Much still remained to be done with respect to radar‑based fire control instruments.[165]

With respect to postwar ammunition research, it was anticipated that the laboratories of several educational institutions would be put to use. The universities of Michigan and Minnesota were to search for an ideal flashless‑smokeless propellant. The University of Arkansas was to attempt to find a tracer‑primer composition which would give optimum performance in all climates. Franklin Institute was to delve into the related problems of rotating bands, the crimping of cartridge cases, chamber clearances, and various forms of rifling. In addition, the Ordnance Research Division of the Bureau of Standards was to continue work with the VT fuze. Research into the characteristics and possibilities of shaped charges, vaned projectiles, and rocket‑assisted artillery shells was also to continue.[166] A wide range of postwar research projects dealing with explosives was planned.[167]

While research into guided missiles was the most important single postwar Ordnance project, research into smaller rockets was also to proceed. Development of high explosive anti‑tank rockets for the 2.36-inch and 3.5-inch launchers, a high explosive rocket for the 4.5-inch launcher, and a 5-inch super‑velocity aircraft rocket was felt to be necessary. A single‑tube, non‑expendable 4.5-inch launcher and multiple launchers capable of firing twenty and twenty‑four rockets of 4.5-inch size were also under continuing development. A study of the characteristics of the various types of rocket propellants (solid, plastic, and liquid) was to be made.[168]

The World War II research and development program of the Ordnance Department resulted in the presentation of 11,286 proposals (between 7 December 1941 and 14 August 1945) for action by the Ordnance Technical Committee. During this period 1,400 major items of equipment, of the 1,800 items in the Ordnance Book of Standards on V‑J Day, were standardized. At the high point of Ordnance development activity, January 1945, 1,347 major research and development projects were receiving attention.[169]

---

[1]      Ordnance Book of Standards, 1940 edition, Research and Development Service, Office of the Chief of Ordnance (OCO).

[2]      Ordnance Book of Standards, 1945 edition, Research and Development Service, Office of the Chief of Ordnance.

[3]      Ordnance Order Number 48, 15 June 1934, subject: Ordnance Laboratories.

[4]      Ordnance Book of Standards, 1940 edition, Groups C, D, and E; Research and Development Service, Office of the Chief of Ordnance.

[5]      Ordnance Project Supporting Paper Number 31, Design, Development and Production of Wheeled Anti‑tank Guns, Volume 1, May 1945, page 2, OHF.

[6]      Ordnance Committee Minutes 15059, 1 June 1939, Research and Development Service, Office of the Chief of Ordnance.

[7]      Ordnance Committee Minutes 15515, 7 December 1939, and Ordnance Committee Minutes 15894, 20 June 1940, Research and Development Service, Office of the Chief of Ordnance.

[8]      Ordnance Committee Minutes 15737, 19 April 1940, and Ordnance Committee Minutes 15791, 9 May 1940, Research and Development Service, Office of the Chief of Ordnance.

[9]      A Study of the Armament, Calibers and Types of Materiel, Kinds and Proportion of Ammunition, and Methods of Transport of the Artillery to be Assigned to a Field Army; Report of a Board of Officers Appointed by Paragraph 142, Special Orders Number 289‑0, War Department, 1918; 5 May 1919, OHF.

[10]    Ordnance Book of Standards, 1940 edition, Groups A and B; Research and Development Service, Office of the Chief of Ordnance.

[11]    Letter, Chief of Infantry to Chief of Ordnance, 25 March 1938, subject: Weapons and Ammunition Carriers, OO 474/3991.

[12]    Ordnance PSP Number 38, Carbine, Caliber .30, Volume 1, July 1944, page 2, OHF.

[13]    7th Ind., AGO to Chief of Ordnance, 27 August 1940, subject: Carbine for Infantry Soldiers, 00 474.5/120.

[14]    Ordnance Book of Standards, 1940 edition, Group G; Research and Development Service, Office of the Chief of Ordnance.

[15]    Ordnance Committee Minutes 15889, 13 June 1940, Research and Development Service, Office of the Chief of Ordnance.

[16]    Ibid., loc. cit.

[17]    Monograph Number 5, History of the Ordnance Department in World War II (for Army Service Forces), 31 December 1945, subject: Combat Vehicles, page 37, OHF.

[18]    Ibid., pages 55‑56.

[19]    Ordnance Book of Standards, 1940 edition, Groups P, R, and V, Research and Development Service, Office of the Chief of Ordnance.

[20]    War Department General Order Number 13, 24 November 1941, Section VIII.

[21]    Ordnance Committee Minutes 16165, 10 October 1940, Research and Development Service, Office of the Chief of Ordnance.

[22]    Monograph, Fire Control for Anti‑aircraft Artillery, undated, Introduction, pages 1‑17, OHF; and Monograph, Development of Combat Vehicles, by Samuel H. Woods, Chief Engineer, Automotive Division, Ordnance Research Center, Aberdeen Proving Ground, October 1943, page 4, OHF.

[23]    Memo, Colonel William A. Borden (Ordnance) for Chief of Staff, 4 September 1943, subject: First Progress Report, Development of Weapons for Jungle Warfare (s), no file number, located in folder tabbed “Jungle Warfare Weapons” in file of Major General G. M. Barnes, Chief, Ordnance Research and Development Service (hereafter cited as “Barnes files”), OHF.

[24]    Report, Eighth Summary of Jungle Warfare Project, Office of the Chief of Staff, 11 June 1944, no file number, (s), Barnes file of “Jungle Warfare Weapons,” OHF.

[25]    Memo, General J. W. Stilwell for Chief of Staff, undated, no subject, included as an inclosure to 00 334/8916 Misc. (s).

[26]    Memo, Director, New Developments Division (NDD), WDGS, for Chief of Staff, 12 May 1945, subject: Equipment for Use Against Japan, included as an enclosure to 00 334/8916 Misc. (5).

[27]    Minutes of the Meeting with General Borden, 14‑15 May 1945, subject: Equipment for Use Against Japan, 00 334/8916 Misc. (s).

[28]    Memo, Chief of Ordnance, NDD, 21 May 1945, subject: Weapons for Cave Warfare at Okinawa, First Progress Report, no file number, Barnes file on “Cave Warfare,” OHF.

[29]    Minutes, Special Division Chiefs Meeting (Research and Development Service) on Cave Warfare in the Pacific Theater, 25 May 1945, page 1, Barnes file on “Cave Warfare,” OHF.

[30]    Memo, Chief of Ordnance for Director, NDD, 28 May 1945 subject: Weapons for Cave Warfare, Second Progress Report, no file number (c), located in Army Ground Forces file concerning “Sphinx Project,” Historical Records Section, AGO.

[31]    Memos, Chief of Ordnance for Director, NDD, 4, 11, and 18 June 1945, subjects: Weapons for Cave Warfare, Third, Fourth, and Fifth Progress Reports, no file numbers (c), located in Army Ground Forces files concerning “Sphinx Project,” Historical Records Section, AGO.

[32]    Memo, Office of the Quartermaster General for G‑4, 25 February 1942, subject: Desert Vehicle Tests, file QM 400.112M‑ES (Tests, Desert).

[33]    History of the Ordnance Desert Proving Ground, Volume 100, 23 March 1945, page 6, OHF.

[34]    Ordnance Order Number 81, Change 1, 24 February 1944, subject: Establishment of Ordnance Desert Proving Ground, Camp Seeley, California.

[35]    AGO Memo Number S‑45‑13‑43, 19 July 1943.

[36]    1st Ind., CG, SCS, for Chief of Ordnance, 10 October 1942, no subject, file 00 400.112/3805.

[37]    History of Aberdeen Proving Ground, Volume II, Chapter 11, undated, subject: Proving Center Winter Detachment, page 8, OHF.

[38]    Ordnance Department Circular Number 235, 19 November 1942, subject: Winter Proving Ground to be Established in Canada.

[39]    History of Aberdeen Proving Ground, Volume IV, Chapter 11, 23 December 1943, subject: Shilo Camp Winter Detachment, pages 10‑16, OHF.

[40]    History of Frankford Arsenal, Fire Control Design Division, Volume V, 3 March 1944, page 27, OHF.

[41]    Letter, Secretary of War to Commanding Officer, Frankford Arsenal, 25 September 1943, subject: Movement Orders, Shipment 6650, file WD 370.5 (23 September 1943) OB‑S‑E‑SPMOT‑M.

[42]    History of Aberdeen Proving Ground, Volume III, 31 October 1944, subject: Arctic Testing 1943‑44-Fire Control Materiel (booklet), pages 19‑36.

[43]    Memo, Commanding General, Army Service Forces, for Chief of Ordnance, 25 September 1943, subject: Automotive Cold Weather Test Activities, Dawson Creek, British Columbia., file SPOPP 322 (22 September 1943).

[44]    History of Office of the Chief of Ordnance-Detroit (OCOD) Development Division, Volume V, 16 May 1944, pages 28‑29, OHF.

[45]    Ordnance Committee Minutes 20075, 1 April 1943, and Ordnance Committee Minutes 20319, 29 April 1943, OHF.

[46]    Ordnance Committee Minutes 25310, 5 October 1944, OHF.

[47]    Monograph, Combat Vehicles, History of the Ordnance Department in World War II (for Army Service Forces), 11 June 1946, pages 36‑38, OHF.

[48]    Ordnance Committee Minutes 24395, 13 July 1944, Research and Development Service, Office of the Chief of Ordnance.

[49]    Monograph, Combat Vehicles, History of the Ordnance Department in World War II (for Army Service Forces), 11 June 1946, pages 38‑40, OHF.

[50]    Ibid., pages 127‑130.

[51]    Ibid., pages 40‑41.

[52]    Ordnance Committee Minutes 27536, 3 May 1945, Research and Development Service, Office of the Chief of Ordnance.

[53]    Monograph, Combat Vehicles, History of the Ordnance Department in World War II (for Army Service Forces), 11 June 1946, pages 41‑42, OHF.

[54]    Ordnance Committee Minutes 17579, 26 December 1941, Research and Development Service, Office of the Chief of Ordnance.

[55]    Ordnance Committee Minutes 18390, 25 June 1942, Research and Development Service, Office of the Chief of Ordnance.

[56]    40mm Gun Motor Carriage, M19, Ordnance Committee Minutes 23746, 11 May 1944, Research and Development Service, Office of the Chief of Ordnance.

[57]    Ordnance Committee Minutes 15889, 13 June 1940, Research and Development Service, Office of the Chief of Ordnance.

[58]    Ordnance Committee Minutes 17450, 21 November 1941, Research and Development Service, Office of the Chief of Ordnance.

[59]    Ordnance Committee Minutes 17642, 15 January 1942, Research and Development Service, Office of the Chief of Ordnance.

[60]    Ordnance Committee Minutes 18120, 23 April 1942, Research and Development Service, Office of the Chief of Ordnance; Ordnance Committee Minutes 18435, 2 July 1942, and Ordnance Committee Minutes 18597, 6 August 1942, Research and Development Service, Office of the Chief of Ordnance.

[61]    Ordnance Committee Minutes 18188, 7 May 1942, Research and Development Service, Office of the Chief of Ordnance.

[62]    Ordnance Committee Minutes 23202, 16 March 1944, Research and Development Service, Office of the Chief of Ordnance.

[63]    Ordnance Committee Minutes 23978 1 June 1944, Research and Development Service, Office of the Chief of Ordnance.

[64]    Ordnance Committee Minutes 25812 23 November 1944, Research and Development Service, Office of the Chief of Ordnance.

[65]    Monograph, Combat Vehicles, History of the Ordnance Department in World War II (for Army Service Forces), 11 June 1946, page 42, OHF.

[66]    Ordnance Committee Minutes 18727, 27 August 1942, Research and Development Service, Office of the Chief of Ordnance.

[67]    Ordnance Committee Minutes 27661, 17 May 1945, and Ordnance Committee Minutes 27763, 24 May 1945, Research and Development Service, Office of the Chief of Ordnance.

[68]    Summary Report of Acceptances of Tank‑Automotive Materiel, 1940‑45, Office of the Chief of Ordnance‑D, 31 December 1945, pages 20‑21, OHF.

[69]    Monograph, Combat Vehicles, History of the Ordnance Department in World War II (for Army Service Forces), 11 June 1946, page 21, OHF.

[70]    Ordnance Committee Minutes 20363, 6 May 1943, Research and Development Service, Office of the Chief of Ordnance.

[71]    Ordnance Committee Minutes 26106, 21 December 1944, Research and Development Service, Office of the Chief of Ordnance.

[72]    Ordnance Committee Minutes 16187, 17 October 1940, Research and Development Service, Office of the Chief of Ordnance.

[73]    Ordnance Committee Minutes 18370, 18 June 1942, and Ordnance Committee Minutes 18509, 16 July 1942, Research and Development Service, Office of the Chief of Ordnance.

[74]    Ordnance Committee Minutes 21142, 22 July 1943, Research and Development Service, Office of the Chief of Ordnance.

[75]    War Department Circular Number 10, 6 January 1944.

[76]    Ordnance Committee Minutes 16409, 16 January 1941; Ordnance Committee Minutes 16521, 27 February 1941; and Ordnance Committee Minutes 21220, 5 August 1943, Research and Development Service, Office of the Chief of Ordnance.

[77]    Ordnance Committee Minutes 18887, 17 September 1942; Ordnance Committee Minutes 19038, 15 October 1942, and Ordnance Committee Minutes 21220, 5 August 1943, Research and Development Service, Office of the Chief of Ordnance.

[78]    Ordnance Committee Minutes 18583, 6 August 1942; Ordnance Committee Minutes 18730, 27 August 1942; and Ordnance Committee Minutes 21220, 5 August 1943, Research and Development Service, Office of the Chief of Ordnance.

[79]    Ordnance Committee Minutes 20938, 13 May 1943; Ordnance Committee Minutes 20715, 10 June 1943; and Ordnance Committee Minutes 21220, 5 August 1943, Research and Development Service, Office of the Chief of Ordnance.

[80]    Monograph, Weapons Innovations, History of the Ordnance Department in World War II (for Army Service Forces), 31 December 1945, pages 15‑18, OHF; Ordnance Committee Minutes 21397, 26 August 1943; and Ordnance Committee Minutes 21627, 23 September 1943, Research and Development Service, Office of the Chief of Ordnance.

[81]    Monograph, Motor Transport Vehicles, History of the Ordnance Department in World War II (for Army Service Forces), 31 December 1945, pages 36‑69, OHF.

[82]    Ordnance Committee Minutes 15938, 11 July 1940; Ordnance Committee Minutes 16724, 15 May 1941; Ordnance Committee Minutes 16726, 15 May 1941; Ordnance Committee Minutes 16830, 12 June 1941, Research and Development Service, Office of the Chief of Ordnance.

[83]    Ordnance Committee Minutes 19910, 11 March 1943; Ordnance Committee Minutes 20688, 10 June 1943; Ordnance Committee Minutes 21293, 12 August 1943; Ordnance Committee Minutes 22735, 27 January 1944, Research and Development Service, Office of the Chief of Ordnance.

[84]    Ordnance Committee Minutes 26989, 15 March 1945, Research and Development Service, Office of the Chief of Ordnance.

[85]    Ordnance Committee Minutes 21286, 12 August 1943, Research and Development Service, Office of the Chief of Ordnance.

[86]    Ordnance Committee Minutes 28638, 2 August 1945; Ordnance Committee Minutes 28822, 23 August 1945, Research and Development Service, Office of the Chief of Ordnance.

[87]    Ordnance Committee Minutes 16279, 22 November 1940; Ordnance Committee Minutes 16741, 21 May 1941; Ordnance Committee Minutes 17018, 24 July 1941, Research and Development Service, Office of the Chief of Ordnance.

[88]    Ordnance Committee Minutes 18332, 11 June 1942; Ordnance Committee Minutes 18865, 10 September 1942, Research and Development Service, Office of the Chief of Ordnance.

[89]    Ordnance Committee Minutes 21243, 5 August 1943; Ordnance Committee Minutes 21512, 9 September 1943; Ordnance Committee Minutes 22131, 18 November 1943; Ordnance Committee Minutes 22187, 25 November 1943, Research and Development Service, Office of the Chief of Ordnance.

[90]    Ordnance Committee Minutes 25324, 5 October 1944; Ordnance Committee Minutes 28987, 6 September 1945, Research and Development Service, Office of the Chief of Ordnance.

[91]    Ordnance Committee Minutes 16647, 24 April 1941; Ordnance Committee Minutes 16755, 22 May 1941; Ordnance Committee Minutes 20401, 13 May 1943; Ordnance Committee Minutes 22734, 27 January 1944, Research and Development Service, Office of the Chief of Ordnance.

[92]    Ordnance Committee Minutes 17545, 18 December 1941; Ordnance Committee Minutes 17888, 5 March 1942, Research and Development Service, Office of the Chief of Ordnance.

[93]    Ordnance PSP Number 40, Submachine Guns, 15 December 1945, pages 7‑18, OHF.

[94]    Ordnance Committee Minutes 17360, 23 October 1941, Research and Development Service, Office of the Chief of Ordnance.

[95]    Ordnance Committee Minutes 18212, 14 May 1942, Research and Development Service, Office of the Chief of Ordnance.

[96]    Ordnance PSP Number 39, Hand Weapons in World War II, 27 August 1945, OHF.

[97]    Ordnance Committee Minutes 17607, 11 December 1941, Research and Development Service, Office of the Chief of Ordnance.

[98]    Ordnance Committee Minutes 18594, 6 August 1942, Research and Development Service, Office of the Chief of Ordnance.

[99]    Ordnance Committee Minutes 22331, 9 December 1943, Research and Development Service, Office of the Chief of Ordnance.

[100] Ordnance Committee Minutes 27463, 26 April 1945, Research and Development Service, Office of the Chief of Ordnance.

[101] Ordnance Committee Minutes 29749, 29 November 1945, Research and Development Service, Office of the Chief of Ordnance.

[102] Ordnance Committee Minutes 17507, 11 December 1941, Research and Development Service, Office of the Chief of Ordnance.

[103] Monograph, Weapons Innovations, History of the Ordnance Department in World War II (for Army Service Forces), 31 December 1945, page 20, OHF.

[104] Ordnance Committee Minutes 27443, 26 April 1945, Research and Development Service, Office of the Chief of Ordnance.

[105] 1st Ind., Commanding General, Army Service Forces, for Chief of Ordnance, 16 March 1944, subject: Gun, Recoilless, 57mm T15E1 (Kromuskit), 00 472.12/ 508 (s).

[106] Ordnance Committee Minutes 28547, 26 July 1945, Research and Development Service, Office of the Chief of Ordnance.

[107] Ordnance Committee Minutes 27924, 7 June 1945, Research and Development Service, Office of the Chief of Ordnance.

[108] Monograph, Weapons Innovations, History of the Ordnance Department in World War II (for Army Service Forces), 31 December 1945, pages 7‑8, OHF.

[109] Ordnance Committee Minutes 19025, 6 October 1942, Research and Development Service, Office of the Chief of Ordnance.

[110] Ordnance Committee Minutes 23345, 30 March 1944; Ordnance Committee Minutes 25652, 2 November 1944, Research and Development Service, Office of the Chief of Ordnance.

[111] Ordnance Committee Minutes 25535, 26 October 1944, Research and Development Service, Office of the Chief of Ordnance.

[112] Ordnance Committee Minutes 19551, 21 January 1943; Ordnance Committee Minutes 23714, 4 May 1944; Ordnance Committee Minutes 25534, 26 October 1944, Research and Development Service, Office of the Chief of Ordnance.

[113] Ordnance Committee Minutes 28717, 9 August 1945, Research and Development Service, Office of the Chief of Ordnance.

[114] Ordnance Committee Minutes 23564, 20 April 1944; Ordnance Committee Minutes 24694, 10 August 1944 Research and Development Service, Office of the Chief of Ordnance.

[115] Monograph, Weapons Innovations, History of the Ordnance Department in World War II (for Army Service Forces), 31 December 1945, pages 31‑40, OHF.

[116] Manual, Allied and Enemy Explosives, undated, Ordnance Bomb Disposal Center, Aberdeen Proving Ground, Maryland, pages 119‑129, OHF.

[117] Ibid., pages 88‑90, 93‑95, 138‑140, OHF.

[118] G. M. Barnes, Weapons of World War II, New York, 1947, page 75.

[119] Manual, Allied and Enemy Explosives, undated, Ordnance Bomb Disposal Center, Aberdeen Proving Ground, Md., page 135, OHF.

[120] Ordnance PSP Number 15, Chemicals in the Powder and Explosives Program, January 1947, pages 5‑6, OHF.

[121] Ordnance Committee Minutes 21139, 22 July 1943, Research and Development Service, Office of the Chief of Ordnance.

[122] Manual, Allied and Enemy Explosives, undated, Ordnance Bomb Disposal Center, Aberdeen Proving Ground, Md., pages 143‑145, OHF.

[123] Barnes, op.cit., pages 73‑110.

[124] Ordnance Committee Minutes 17233, 18 September 1941; Ordnance Committee Minutes 17234, 18 September 1941; Ordnance Committee Minutes 21745, 7 October 1943; Ordnance Committee Minutes 27391, 19 April 1945, Research and Development Service, Office of the Chief of Ordnance.

[125] Ordnance Committee Minutes 21931, 28 October 1943; Ordnance Committee Minutes 22517, 30 December 1943, Research and Development Service, Office of the Chief of Ordnance.

[126] Ordnance Committee Minutes 16492, 20 February 1941; Ordnance Committee Minutes 17599, 8 January 1945; Ordnance Committee Minutes 21926, 28 October 1943; Ordnance Committee Minutes 24765, 17 August 1944; Ordnance Committee Minutes 27464, 26 April 1945, Research and Development Service, Office of the Chief of Ordnance.

[127] Ordnance Committee Minutes 17279, 30 September 1941; Ordnance Committee Minutes 22729, 27 January 1944, Research and Development Service, Office of the Chief of Ordnance.

[128] Ordnance Committee Minutes 17270, 9 September 1941; Ordnance Committee Minutes 19694, 11 February 1943; Ordnance Committee Minutes 22551, 6 January 1944, Research and Development Service, Office of the Chief of Ordnance.

[129] Ordnance Committee Minutes 1 7599, 8 January 1942, Research and Development Service, Office of the Chief of Ordnance.

[130] Ordnance Committee Minutes 17339, 16 October 1941, Research and Development Service, Office of the Chief of Ordnance.

[131] Ordnance Committee Minutes 18040, 9 April 1942, Research and Development Service, Office of the Chief of Ordnance.

[132] Ordnance Committee Minutes 25838, 23 November 1944, Research and Development Service, Office of the Chief of Ordnance.

[133] Ordnance Committee Minutes 18460, 30 June 1942, Research and Development Service, Office of the Chief of Ordnance.

[134] Ordnance Committee Minutes 25125, 14 September 1944, Research and Development Service, Office of the Chief of Ordnance.

[135] Ordnance PSP Number 20, Rockets, May 1945, page 28, OHF.

[136] Ordnance Committee Minutes 27395, 19 April 1945, Research and Development Service, Office of the Chief of Ordnance.

[137] Ordnance Committee Minutes 27687, 17 May 1945, Research and Development Service, Office of the Chief of Ordnance.

[138] Ordnance Committee Minutes 20536, 27 May 1943, Research and Development Service, Office of the Chief of Ordnance.

[139] Ordnance Committee Minutes 29817 and 29818, 6 December 1945, Research and Development Service, Office of the Chief of Ordnance.

[140] Detailed discussion of the development of solventless rocket powder may be found in Ordnance PSP Number 17, Solventless Rocket Powder Program, July 1945, OHF.

[141] Ordnance Committee Minutes 18040, 9 April 1942; Ordnance Committee Minutes 23649, 27 April 1944; Ordnance Committee Minutes 25769, 16 November 1944; Ordnance Committee Minutes 24964, 31 August 1944; Ordnance Committee Minutes 29655, 8 November 1945, Research and Development Service, Office of the Chief of Ordnance.

[142] Ordnance PSP Number 82, Research and Materials, June 1947, pages 74‑76, OHF.

[143] Barnes, op.cit., pages 295‑296.

[144] Ordnance PSP Number 82, Research and Materials, June 1947, pages 78‑83, OHF.

[145] Ibid., pages 85‑87.

[146] Barnes, op.cit., page 297.

[147] Ordnance PSP Number 53, Rubber, July 1945, pages 9‑10, OHF.

[148] Ibid., pages 13‑14. Details of the rubber development program as it affected tires may be found in pages 31‑109; other items pages 111‑150.

[149] History of Watertown Arsenal, Volume XV, April 1944, and XV, Supplement 1, June 1945, OHF.

[150] Ordnance PSP Number 82, Research and Materials, June 1947, pages 106‑117, OHF.

[151] Diary of Major General G. M. Barnes, Chief Research and Development Service, Office of the Chief of Ordnance, 3 February 1942, OHF.

[152] Ibid., 13 May and 3 June 1942.

[153] Major General G. M. Barnes, Supersonic Wind Tunnel Laboratory, Mechanical Engineering, Volume 67 Number 12, December 1945, page 833.

[154] Barnes, Weapons of World War II, pages 301‑302.

[155] History of Aberdeen Proving Ground, Volume II, Chapter 5, pages 5, 7, 6, OHF.

[156] Barnes, op.cit., pages 302‑303.

[157] Ibid., pages 300‑301.

[158] Ordnance PSP Number 84, Firing Tables, May 1947, pages 27‑28, OHF.

[159] Ordnance PSP Number 82, Research and Materials, June 1947, page 113, OHF.

[160] Minutes of Joint Army‑Navy Meeting on Army Ordnance Research and Development (s), 1 October 1945, page 1, Research and Development Service, Office of the Chief of Ordnance.

[161] Report of Research and Development Service to the Ordnance Central Projects Integrating Committee, 2 June 1945, pages 1‑3, OHF.

[162] Minutes of Joint Army‑Navy Meeting on Army Ordnance Research and Development (s), 1 October 1945, pages 8‑18, Research and Development Service, Office of the Chief of Ordnance.

[163] Ibid., pages 18‑21.

[164] Ordnance Committee Minutes 28799, 20 August 1945, Research and Development Service, Office of the Chief of Ordnance.

[165] Minutes of Joint Army‑Navy Meeting on Army Research and Development (s), 1 October 1945, pages 22‑27, Research and Development Service, Office of the Chief of Ordnance.

[166] Ibid., pages 28‑34.

[167] Ordnance Committee Minutes 28794 (3), 20 August 1945, Research and Development Service, Office of the Chief of Ordnance.

[168] Minutes of Joint Army‑Navy Meeting on Army Research and Development (s), 1 October 1945, pages 37‑39, Research and Development Service, Office of the Chief of Ordnance.

[169] Ibid., page 1.

Semi-Automatic Rifle M1 (Garand).

Model 1928A1 Thompson Submachine Gun.

Submachine Gun M3.

Browning Automatic Rifle (BAR) Model 1922.

Browning .50 caliber Heavy Machine Gun M2 on tripod for ground use.

Fragmentation Hand Grenade Mk. II A1.

57mm Recoilless Gun.

75mm Recoilless Gun.

Truck, ¼-ton, 4 × 4 (Jeep).

2½ ton Truck 6 × 6 M32.

Light Tank M3 “General Stuart.

Medium Tank M3 “General Grant.”

Medium Tank M4 “General Sherman”.

Medium Tank M26 “General Pershing.”

8-inch Howitzer M8.

240mm Howitzer. The weapon traveled in two pieces: Top—the carriage on its trailer being towed by the High-Speed Tractor M8; Bottom—barrel with ring cradle and recoil system on its traveling trailer.

105mm Howitzer Motor Carriage M7 “Priest.”

155mm Howitzer Motor Carriage M41.

155mm Gun Motor Carriage M12.

240mm Howitzer Motor Carriage T92 “King Kong.”

4.2-inch Mortar.

36-inch Mortar “Little David.”

90mm Anti-tank Gun T9.

120mm Anti-Aircraft Gun.

90mm Anti-aircraft Gun.

Colt Automatic M1911A1.

American troops with M1 Garands, Pacific.

American troops firing M1 carbines, Pacific.

American troops wade across a river, Pacific. The soldier nearest the camera shoulders an M1 carbine with ammo pouches attached to the butt stock.

American  sniper with Springfield ’03 rifle, in jungle camouflage uniform with netting face mask and gloves to conceal his flesh tones, 1943.

Browning Automatic Rifle Model (BAR) 1918A2. 

American fires a BAR at a group of Japanese changing positions.

Thompson submachine gun.

Thompson M1 submachine gun, without its box magazine.

M1928 Thompson submachine gun, which could use box or drum magazines.

American troops firing an M1928A1 Thompson submachine gun and M1 Garand rifle, Pacific.

American light machine gun .30 caliber T-66.

Browning water-cooled .50-caliber machine gun used for anti-aircraft defense.

M2 .50-cal. water-cooled machine gun on anti-aircraft mount, Pacific.

M1919A4 .30-cal. air-cooled machine gun on tripod mount, Pacific.

Field modification creating a mobile .50 caliber machine gun utilizing a trailer carriage that could be towed by a jeep and quickly brought into action.

American troops with M1 Garand rifles, M1 carbines and a flamethrower, Pacific.

A demonstration of an M1 flame gun against a bunker. If the occupants were not caught in the flames, they were overcome when the oxygen inside the emplacement was exhausted. Allied flamethrowers, unlike German weapons, could project unignited fuel through a bunker embrasure, and then follow it with a burst of flame.

During training at Edgewood Arsenal, Maryland, troops use M2-2 man-pack flamethrowers in a simulated attack. They are covered by two men with BARs. Allied flamethrowers were designed to produce a bushy flame which was found to have greater psychological effect.

60mm Mortar M2, Mount M2.

60mm Mortar M19, Mount M1.

81mm Mortar M1, Mount M1.

81mm Mortar with extension tube T1.

Two views of the 4.2-inch Chemical Mortar.

105mm Mortar T13, Mount T12.

155mm Mortar T25, Mount T16E2.

155mm Mortar T25, Mount T16E2, in action in the Pacific.

M1 81mm mortar, Pacific.

4.2-inch mortars, Pacific.

105mm Howitzer M2A1s on a training range. In the foreground is a 37mm sub-caliber barrel that was used mounted over the barrel during training to decrease costs by firing smaller caliber and cheaper ammunition and to reduce wear and tear on the howitzer barrels.

Number two piece, C Battery, 880th Field Artillery Bn., immediately after firing the first round fired by the 69th Division Artillery in combat. Round was fired at 1050 hours on 11 February 1945.

105mm howitzer.

105mm Howitzer M3 on Carriage M3A1.

Artillery crews of the Seventh Army, November 1944, wearing M1943 combat dress, without equipment.

Two Soldiers proudly show off their personalized “Easter eggs” before firing them.

105mm Howitzer M3 on Carriage M3A1.

8-inch M1 howitzer in action as its black crew prepare to lift the 200-pound shell for loading into the breech.

Aberdeen Proving Ground, Maryland. Lieutenant Guy H. Drewry, U.S.A. (center), aide-de-camp to Major General Charles T. Harris, Jr., commanding the Aberdeen Proving Ground, pointing out important features of the 8 inch howitzer to Chinese Major-General Dai-Fung King (right) and his aide-de-camp, Captain Zeit Wang (left). The two are members of the Chinese military mission to the United States. 1942.

240mm howitzer.

155mm M2 gun “Long Tom,” Pacific.

155mm howitzer.

75mm Pack Howitzer M1A1 on Carriage M1.

75mm Pack Howitzer M1A1 on Carriage M1.

75mm Pack Howitzer M1A1 on Carriage M8.

British Airborne troops in training with American 75mm Pack Howitzer, December 1943.

75mm Pack Howitzer lashed in a Hamilcar glider.

155mm howitzer in action during training.

90mm anti-aircraft gun in a well-built emplacement.

American troops assembling the barrel of a 40mm (Bofors) anti-aircraft gun.

3-inch anti-aircraft gun M3 on mount M2A2.

40mm anti-aircraft gun manned by black soldiers.

90mm M1 anti-aircraft gun on mount M1A1 dug in as part of a beach defense. The battery rangefinder can be seen in another pit at left rear.

90mm anti-aircraft gun, Pacific.

40mm (Bofors) anti-aircraft gun.

40mm anti-aircraft gun, Pacific.

120mm anti-aircraft gun.

20mm anti-aircraft gun, Pacific.

Pre-war photo of 3-inch anti-aircraft gun M2. This type saw service in the Philippines during the early months of the war.

Marine sergeant transporting anti-aircraft gun with an International crawler tractor, 1941.

40mm Gun Carriage M5 (Airborne).

40mm Gun Carriage M5 (Airborne) in traveling order.

Anti-tank guns being demonstrated in 1942: the 37mm M3A1 and the 3-inch M5.

37mm anti-tank gun, Pacific.

57mm anti-tank gun, Pacific.

M1 and M6 towed 3-inch anti-tank guns.

T5E2 90mm anti-tank gun carriage.

Peep towing a 37mm anti-tank gun.

Jeep towing a 37 mm anti-tank gun followed by another jeep.

M1 bazooka in action, Pacific.

An early version of the 2.36-inch rocket launcher (“Bazooka”).

M3A3 medium tank, with 75mm gun in hull and 37mm gun in turret.

Early production model M3 Medium Tank.

Medium Tank M4A4 (75mm).

Medium Tank M4A3E8 (76mm).

M4, International Harvester's Bettendorf Works, 1942.

M4s gathered on a hillside. Note that all but one have overpainted the white star with black paint to eliminate the ability of the enemy to use the star as a convenient aiming point.

 

Very late production M4 medium tank with combination cast/rolled glacis and M34A1 gun mount. Fitted with fording kit.

M4 medium tank at International Harvester's Bettendorf Works in 1942.

M4 with track extensions (grousers) coming off of the assembly line, International Harvester's Bettendorf Works, 1942.

Late production M4A1 medium tank with M34A1 gun mount.

Early M4A2 medium tanks in production at Fisher Body, early 1942.

Early production M4A4 medium tank with vision blocks and M34 gun mount.

Light Tank M3.

The 1,000th M3 Light Tank manufactured by American Car and Foundry Company, Berwick, Pennsylvania.

M3A1 light tank, Guadalcanal.

Crew of an M3 light tank with all of their weapons, equipment and personal belongings.

Light Tank M5A1, General Motors Proving Ground, 14 June 1943.

Light Tank M5A1, General Motors Proving Ground, 14 June 1943.

Light Tank M24.

M24 light tank, 117th Cavalry Reconnaissance Squadron, France, 1945.

LVT-1, right side (1941). The first military model. Traveling at a respectable six knots in the water and 12 mph on land, it could deliver 24 fully-equipped assault troops to the beach, and supply supporting fire from two .30-cal. machine guns. San Diego, California, 1942.

LVT-1, Solomons.

Right side view of the LVT(A)-4 tank mounting the turret from the Howitzer Motor Carriage M8 with a 75mm howitzer. March 1944. Another fire support version, with 75mm Howitzer Motor Carriage M8 turret armed with a 75mm howitzer, in some cases replaced with the Canadian Ronson flamethrower.

Upper view of the LVT(A)-4 tank mounting the turret from the Howitzer Motor Carriage M8 with a 75mm howitzer. March 1944. A single .50-cal. machine gun was installed on the ring mount above the turret rear. In the late production vehicles the heavy machine gun was replaced with two M1919A4 .30-cal. machine guns on pintle mounts and one more in the bow mount. 1,890 units produced.

75mm M3 GMC half-track.

The crew of this 75mm M3 gun motor carriage are wearing the 1941 twill summer combat dress with full equipment.

M3A2 half-track.

M3A1 Half-track.

M36 (T71) Gun Motor Carriage, 90mm, Aberdeen Proving Ground, 30 June 1944.

T83 155mm gun motor carriage was standardized as the M40 GMC.

M8 armored car.

M20 armored car.

DUKW Amphibious Truck lands on a beach with a load of cargo.

DUKW Amphibious Truck comes ashore on a beach.

DUKW Amphibious Truck being loaded with cargo.

76mm Howitzer Motor Carriage M8, General Motors Proving Ground, 4 November 1943.

76mm Howitzer Motor Carriage M8, General Motors Proving Ground, 4 November 1943.

M6 heavy tank.

Upper rear view of an M6 heavy tank.