American Half-tracks

40th Tank Battalion, 7th Armored Division, M3 Half-track with jeep, tanks in background during desert maneuvers, 1943.

The U.S. half-track is usually perceived as having been a sturdy, reliable, well-designed and well-protected quasi-tank. In actuality, it was anything but. And while it’s true that U.S. half-tracks were not underpowered as was the German Sd.Kfz. 251, that was about their only virtue.

Their armor plating (and most everything else) was continually vibrating loose (one writer described driving one on an improved road as “rather like driving a ten-ton kitchen cabinet on a washboard”).

Their floors were unarmored and gave no protection against mines—unlike their German counterparts; their side armor could be pierced by .50-cal. armor-piercing rounds at over 1,000 meters, and even by .30-cal. AP rounds out to 350 meters (the figures for the more heavily armored and ballistically well-sloped Sd.Kfz. 251 are about 600 meters and 30 meters respectively). And their tracks had about twenty-five per cent less ground contact area than those of the Sd.Kfz. 251 (al-though the U.S. half-track had driven front wheels while the German didn’t).

Speaking of tracks, the German tracks were very sophisticated, expensive, and maintenance intensive—but they were not plagued by frequent breakdowns. They did have a tendency to bind up if packed with mud or snow, but this seems to have been a problem only when the vehicle had been motionless long enough for the substance to freeze. On the other hand, U.S. tracks wore out quickly due to their construction, which consisted of steel plates attached to a loop of steel cables, with the whole assembly being covered with vulcanized rubber. At high speed (even on paved roads) or in loose terrain, the rubber was flung off by centrifugal force and/or abraded by the ground material, thus exposing the plates and cables and causing thrown tracks and damaged boogie wheels. “Even with good tracks, good boogie wheels, and proper tension, tracks were often thrown at inconvenient times” (R. Fines, as previously noted). The commander of the 1st Armored Division stated in a report to Allied Forces Headquarters (dated 13 June 1943) that half-tracks “have been continually subject to the throwing of tracks” and went on to declare that they were more trouble than they were worth and should be replaced by trucks!

This might sound incredible to readers who for so long had envisioned armored infantry assaults with squads ensconced in half-tracks; but in reality, such occurrences were rare. The infantry almost invariably dismounted to fight. It’s not surprising, considering the above penetration specs! And would it be any more surprising, in view of all of the above, if U.S. half-track drivers tended to be cautious when their vehicles were in close proximity to the enemy; moreover, would it be any more surprising that a half-track would sometimes throw a track at an inopportune moment?

The German half-tracks were far from perfect, but they were the product of a long design and development period and were generally superior for this reason, in contrast to the American design whose creation was somewhat of a fortuitous accident and whose production was halted even before the war’s end, in early 1944.

M2 Half-track Car

The M2 Half Track was an half-track armored vehicle produced by the United States during World War II. It was based on Half-tracks brought in from France in the 1930s. It was made by the White Motor Company in 1940.

A similar vehicle was built by International Harvester Company as the M9 half-track.

The half-track design had been evaluated by the U.S. Ordnance department using Citroën-Kégresse vehicles.

The Cavalry arm of the U.S. Army found that their wheeled armored scout cars had trouble in rainy weather due to weight and high ground pressure.

In 1938, the White Motor Company took the Timken rear bogie assembly from a T9 half-track truck and added it to an M3 Scout Car, creating the T7 Half-Track Car. This vehicle was woefully underpowered, and when a further requirement came down from U.S. Army artillery units in 1939 for a prime mover (artillery tractor), a vehicle with an uprated engine was devised, then designated the Half Track Scout Car T14.

By 1940, the vehicle had been standardized as the M2 Half-Track car. The M2 design was recognized as having the potential for general mechanized infantry use and with a larger body the M3 Half Track was created. Both the M2 and M3 were ordered into production in late 1940. M2 contracts were placed with the Autocar Company, White and Diamond-T. The first vehicles were received by the army in 1941.

It was supplied to artillery units as prime mover and ammunition carrier for the 105mm howitzer, for armored infantry units to carry machine gun squads, and to armored reconnaissance units. For the latter it was to be an interim solution, until more specialized vehicles could be fielded.

Between 1942 and 1943, these vehicles, just like the larger M3s, would receive a number of modifications to the drive train, engine, and stowage, among other things.

Total production of M2 and derivatives was about 13,500 units. Later, to meet the needs of the Lend-Lease program, the International Harvester Company was brought in to manufacture vehicles similar to the M2, these M9 vehicles totaled a further 3,500 units.

The first M2s were fielded in 1941, and would be used in the Philippines, North Africa, and Europe by the U.S. Army, and around the Pacific by the Marines. About 800 M2 and M9 half-tracks were sent to the Soviet Union. Many remaining vehicles initially destined for lend-lease were transferred to other U.S. allies, primarily in South America. These vehicles often received a number of upgrades designed at extending service life. Nicaragua’s National Guard received 10 M2s in 1942, which saw heavy action during the 1978-79 Nicaraguan Revolution. The Argentine Army retired its last upgraded M9 in 2006 and donated them to Bolivia.

In 1947 the Finnish heavy vehicle producer Vanajan Autotehdas bought 425 M2 Half-track vehicles from the Western Allied surplus stocks located in France and Germany. The vehicles were delivered without armor. 359 units were converted field and forest clearing vehicles, some were scrapped for parts and 60 units were equipped with conventional rear axles and converted into 4×4 or 4×2 trucks. They were badged as Vanaja VaWh. The last units were sold in 1952.

Prime Mover/Scout Vehicle Variants

M2: White Half-Track with White 160AX engine. Fitted with a skate rail mount, featuring an M2HB machine gun.

M9: International Harvester built half-track, developed to complement the M2 for Lend-Lease, but did not feature the short hull of the M2. Also, did not feature the rear access doors, and is outwardly very similar to the M5, but with a different internal configuration.

M9A1: As for the M2A1, an M9 with the M49 machine gun mount. The M9A1 had a rear door.

M2E6/M2A1: Any vehicle with the improved M49 machine gun ring mount over the right hand front seat. Three fixed pintle mounts for 0.30 machine guns were often fitted at the unit level in the field.

Self-propelled Gun Variants

M4/M4A1 81mm MMC: M2 based Motor Mortar Carriage equipped with the 81 mm M1 mortar. The mortar was intended to be fired dismounted from the vehicle, but could be fired in an emergency to the rear from a base inside the vehicle. The A1 modification allowed the weapon to be fixed facing forward and fired from within the vehicle.

M2 with M3 37 mm: Mechanized infantry units in the U.S. Army were supposed to receive the M6 Gun Motor Carriage, based on Dodge light trucks. With the overall failure in combat of these vehicles, some units removed the M3 37 mm gun and its assembly and mounted them on M2 Half-Track Cars.

Anti-aircraft Variants

T1E1: M2 based mobile anti-aircraft gun featuring an open rear with a Bendix mount featuring two .50 inch (12.7 mm) M2 machine guns. The Bendix mount proved to be unsatisfactory. Prototype only.

T1E2: T-1 with Maxson M33 mount in the place of the Bendix mount. The M33 mount also featured two .50 inch M2 machine guns. Would be developed into the M3 based T1E4.

T1E3: T-1 fitted with a partial hard top and a Martin turret, identical to that used on the Boeing B-17 Flying Fortress. Proved to be overly complicated and was ill-suited to the space available in the M2. Prototype only.

T28 CGMC: M2 based Combination Gun Motor Carriage with a single 37 mm Gun M1A2 autocannon flanked by two .50 inch M2 machine guns. The side armor was removed in order to make room for the mount. The project was canceled in 1942 but then revived the same year, when a decision was made to use the longer M3 Half-Track Personnel Carrier chassis for the subsequent T28E1

T10: Variant to test the feasibility of mounting U.S. made copies of the Hispano-Suiza HS.404 20 mm cannon on modified Maxson mounts. Developed into the T-10E1 based on the longer M3 Half Track Personnel Carrier chassis.

M3 Half-Track

The Carrier, Personnel Half-track M3 was an armored vehicle used by the United States, the British Empire and the other Allies during World War II and the Cold War. About 15,000 M3 were produced. Derivative variants and complementary production of similar vehicles amounted to more than 50,000 vehicles.

The M3 and its variants were supplied to the U.S. Army and Marines, as well as British Commonwealth and Soviet Red Army forces, serving on all fronts throughout the war.

Between the world wars, the U.S. Army sought to improve the tactical mobility of its forces. With the goal of finding a high-mobility infantry vehicle, the Ordnance Department had evaluated the half-track design by testing French Citroën-Kégresse vehicles. The White Motor Company produced a prototype half-track using their own chassis and the body of the M3 Scout Car.

The design, using as many commercial components as possible to improve reliability and rate of production, was standardized in 1940 and built by the Autocar Company, Diamond T Motor Company, and the White Motor Company.

Offered with a choice of White 160AX or IHC RED DIAMOND 450 engines, the M3 was driven through a manual constant-mesh (non-synchromesh) transmission with four forward and one reverse gear, as well as a two-speed transfer case. Front suspension was leaf spring, tracks by vertical volute spring. Braking was vacuum-assisted hydraulic, steering manual, without power assist. The electrical system was 12-volt.

The M3 was the larger and longer counterpart to the M2 Half Track Car. The M2 was originally intended to function as an artillery tractor. The M3 had a single access door in the rear and seating for a 12-man rifle squad. Five seats were arranged on each side in the rear of the vehicle and three seats inside the cab.

Racks under the seats were used for ammunition and rations; additional racks behind the seat backs held the squad’s rifles and other stowage. A small rack for mines was added on the outside of the hull just above the tracks. In combat, most units found it necessary to stow additional food, rucksacks and other crew stowage on the outside of the vehicle. Luggage racks were often added in the field, and very late vehicles had rear-mounted racks for this crew stowage.

Early vehicles had a pintle mount just behind the front seats mounting a .50-caliber (12.7 mm) M2 Browning machine gun. The later M3A1 adopted a raised, armored ‘pulpit mount’ for the .50-caliber, and .30-caliber (7.62 mm) machine guns could be used from mounts along the sides of the passenger compartment. Many M3s were later modified to the M3A1 standard. The body was armored all around, with an adjustable armored shutter for the engine’s radiator and a bulletproof windscreen.

The half-tracks were initially extremely unpopular and dubbed “Purple Heart Boxes” (a grim reference to the U.S. Army’s decoration for combat wounds) by American troops. Chief complaints centered around the complete lack of overhead protection from air-bursting artillery shells and that the armor was inadequate against machine gun fire.

Total production of the M3 ran to nearly 41,000 vehicles. To supply the Allied nations International Harvester produced several thousand of a very similar vehicle, the M5 Half-track for Lend-Lease.

Armored Personnel Carrier Variants

M3: White Half-Track with White 386 in3 (6,330 cc) 160AX engine. Fitted with either an M32 anti-aircraft machine gun mount or a pedestal mount, both featuring an M2HB machine gun.

M3A1: Any vehicle with the improved M49 machine gun ring mount over the right hand front seat. Between 1942 and 1943 all M3 Half-Tracks (standard and A1s) were continually upgraded. These improvements included a number of drive train, engine, and stowage improvements.

T29/M3A2: Developed in 1943 to combine features such that existing M2 and M3 production could be switched to a common vehicle. Came at a time where the need for additional half-tracks turned out to be not as great as projected. The M3A2 was, therefore, not produced.

M3E2/M5 Half-track: International Harvester Half-Track, externally largely identical to the M3, but with 450 in3 (7,400 cc). IHC RED-450-B engine, different drive train and fuel and electrical system. In fact, only the chassis, bogies, track, idler and drive sprockets, wheels, winches, transfer case, rollers, and machine gun mount were interchangeable. The M5 is heavier than the M3, due in part to heavier armor. Its body was welded, rather than bolted. The M5 was primarily for Lend-Lease, to Britain, Canada, France, and the Soviet Union.

M5A1: As for the M3A1, an M5 with the M49 machine gun mount. It could fit one .50-caliber (12.7 mm) and two .30-caliber (30.06) machine guns. The IHC models had a slightly lower top speed (only 42 mph (68 km/h)) and lower range (125 mi (201 km)) as well.

T31/M5A2: Similar in principle to the M3A2, a vehicle developed by the U.S. Ordnance Department to combine the production of the M5 and M9 into a single vehicle. As with the M3A2, the projected need was never seen, and this version was never produced en masse.

M9 Half-track: Same vehicle as the M5, with stowage arranged as in the M2 half-track, with access to radios from inside (as opposed to outside) and rear doors, plus pedestal MG mount.

M9A1: Same as M9, with ring mount and three MG pintles.

Self-propelled Gun Variants

T12/M3 75mm GMC: M3 based Gun Motor Carriage equipped with the M1897A5 75 mm gun. These guns were fitted with the gun’s M2A3 ground carriage and its gun shield. Later variants featured a purpose-built gun shield (59 rounds).

M3A1 75 mm GMC: The M2A2 gun carriage was substituted for the A3, as stocks were exhausted. Later variants featured a purpose-built gun shield.

T12 HMC: M3 based Howitzer Motor Carriage equipped with the 75 or 105 mm Pack Howitzer by the U.S. Marine Corps.

T48 Gun Motor Carriage: M3 based Gun Motor Carriage equipped with the M1 57 mm gun, an American copy of the British QF 6 pounder anti-tank gun. A total of 962 T48s were produced during the war. Of these, 60 were supplied under lend lease to Britain, and 650 to the USSR - who called it SU-57 (99 rounds)

T30 75 mm HMC: M3 based Howitzer Motor Carriage equipped with the M1A1 75 mm howitzer in a simple box mount (60 rounds). Used by the U.S. Army. Also provided to the Free French Army, later used in Indochina.

T38 105 mm HMC: M3 based Howitzer Motor Carriage equipped with the M3 105 mm howitzer. Cancelled with the success of the T19.

T19 105 mm HMC: M3 based Howitzer Motor Carriage equipped with the M2A1 105 mm howitzer (8 rounds).

T19/M21 81 mm MMC: M3 based Motor Mortar Carriage equipped with the M1 mortar (81 mm)(97 rounds), designed to allow the mortar to be fired from within the vehicle.

T21: M3 based mortar carrier fitted with a 4.2 inch mortar. Never adopted.

T21E1: The T21’s mortar could only fire rearward as with the M2 based M4 MMC. The T21E1 reoriented to the mortar to fire forward.

Anti-aircraft Variants

T1E4/M13 Half-track: M3 based Multiple Gun Motor Carriage equipped with the Maxson M33 mount with 2 M2HB machine guns (5,000 rounds). The T1E4 prototypes had the hull sides removed for easy of working with the mount. These were reintroduced on production M13s. This was a development of previous T1s that had all been based on the M2 Half-track Car.

M14 Half-track: M13 MGMC variant, based on the M5 chassis. Supplied under lend-lease to Britain (5,000 rounds).

M16 Half-track: M3 based Multiple Gun Motor Carriage equipped with the Maxson M45 Quad mount (specifically the M45D) with 4 M2HB machine guns (5,000 rounds).

M16A1 MGMC: Standard M3 Personnel Carriers converted to Multiple Gun Motor Carriages by removing rear seats and installing a Maxson M45 mount (more specifically the M45F, which featured folding “bat wing” gun shields on both sides of the mount over the machine guns). These vehicles are easily identified by the lack of the folding armored hull panels found on purpose-built M16s.

M16A2 MGMC: M16 MGMC variant, basically M16s brought up to M16A1 standard and with the addition of a rear door to the hull compartment. For existing M16s, this essentially meant a replacement of the M45D mount for the M45F mount.

M17 Half-track: M16 MGMC variant, based on the M5 chassis. Sent under lend-lease to USSR (5,000 rounds).

T58: Similar to the M16/M17, the T58 featured the Maxon quad-mount fitted to a special electric powered turret. Prototype only.

T28E1 CGMC: M3 based Combination Gun Motor Carriage equipped with one M1A2 37mm autocannon (240 rounds) flanked by 2 M2WC machine guns (3,400 rounds). The original T28 had been based on the shorter M2 Half-Track Car chassis.

M15 Half-track: T28E1 variant, equipped with an armored superstructure on the turreted mount to provide crew protection, and switched to M2HB machine guns.

M15A1 CGMC: Reorganization of the weapons, with the M2HB machine guns being fitted under the M1A2 37 mm autocannon instead of above as on the M15.

T10E1: Variant to test the feasibility of mounting U.S. made copies of the Hispano-Suiza HS.404 20 mm cannon on modified Maxson mounts. All were later rebuilt as M16s. The original T10 was based on the shorter M2 Half-Track Car chassis.

40 mm Experiments: Various attempts were made to mate the 40 mm Bofors L/50 gun to the M3 chassis. In all cases the weapon’s recoil was too severe or the mounting too heavy, and the attempts were finally stopped with the adoption of the M19 MGMC on the M24 light tank chassis.

T54/E1: Tested in 1942, the gun mount quickly proved to be unstable when fired, and the improved T54E1, which also added a circular armored shield and rear armor to the vehicle, could not fix the inherent problem. Prototype only.

T59: A development of the T54/E1, fitted with outriggers to help stabilize the vehicle during sustained firing. Still proved to be too unstable for anti-aircraft use. Prototype only.

T59E1: T59 fitted with the T17 fire control system. Prototype only.

T60/E1: Similar to the T54 and the T59, but featured two .50 caliber M2 machine guns flanking the 40 mm cannon (the mounting’s designation was T65). The T60E1 featured an armor configuration similar to that of the T54E1. Suffered from the same stability issues of previous attempts. Prototype only.

T68: Perhaps the most radical of the experiments, the T68 featured two 40 mm cannons, one mounted on top of the other, plus a stabilizer on top of the two guns. The recoil force proved to be too much for the mount, and the idea was abandoned. Prototype only.

M15 “Special”: Field conversions by U.S. Army depots in Australia of standard M3s, not M15s, fitted with turreted 40 mm Bofors L/50 guns. These were the only successful mating of this weapon to the M3 chassis, and were used more for direct fire support than for anti-aircraft purposes.

M34 “Special”: Like the M15 “Special” above, 102 M15s were converted to M34s in Japan in 1951. The M34 mounted a single 40mm Bofors gun in place of the M15’s combination gun mount. This was due primarily to a shortage of 37mm ammunition, which was no longer manufactured. M34s served with at least two AAA (automatic weapons) battalions (the 26th and 140th) in the Korean War.

M5 Half-track

The Carrier, Personnel Half-track M5 was an armored personnel carrier of World War II. It was produced in the United States by International Harvester as a supplement to production of the M3 Half-track. It was supplied to Allied nations (the British Commonwealth, France, and the Soviet Union) under the Lend-Lease.

The M9 Half-Track was the same vehicle but with a different internal layout to fulfill the same purpose as the M2 Half Track Car.

In 1942, the U.S. faced a demand for a greater supply of M3 half-tracks to the Allies and the existing manufacturers could not provide these. International Harvester could build them but changes in components and construction were necessary. Due to a lack of face-hardened armor, homogenous armor was used. Although thicker at 5/16 inch to the M3’s ¼-inch, it was effectively less protection – armor piercing rifle caliber bullets could penetrate it at 300 yds rather than 200 yds for the M3. At the same time IH was to produce a version of the M2 Half Track Car.

The first production of the M5 were completed in December 1943. Changes to the demand for half-tracks led to reduced orders within the U.S. Army, and the M5 became “limited standard” for the U.S., and most all M5 were sent for Allied use. The added weight of the armor reduced the speed to 42 mph, and range was reduced to 125 miles.

During the war the majority of M5 (and M9) production went to the UK which then passed them on to Commonwealth forces or other allies operating with the British Army such as Free Polish or Free Czech forces. The USSR received supplies directly. In British service they were used as utility vehicles for Royal Engineers units, or to motor battalions instead of 15cwt trucks for towing anti-tank guns.

After the war, half-tracks were provided under the Military Aid Program.

Variants

M3E2/M5: An International Harvester Half-track. Virtually identical to the M3. The only differences was the thicker armor (up to 20 mm), different engine (IHC RED-450-B), and lower range (125 mi (201 km)). This model was mainly supplied to the Soviet Union, the British Commonwealth, and France. 4625 produced.

M5A1: M5 with a M49 machine gun mount. It could fit one 0.5 inch (12.7 mm) M2 Browning heavy machine gun, and two 0.3 inch M1919 Browning machine guns. 2159 produced

M5A2: Similar to the M3A2, the M5A2 is was a combination of the M5 and M9 Half-tracks. This was only a projected vehicle that was never produced en-masse.

M9: Same as the M5, stowage arranged as the M2 Half-track, with access to radios from inside (as opposed to outside) and rear doors, plus pedestal machine gun mount. 2026 produced

M9A1: Same as M9, with ring mount and three machine gun pintles. 1,407 produced.

M14 Half-track: A version of the M13 Multiple Gun Motor Carriage (based on the M5). It had two 0.5 inch machine guns mounted in a Maxson turret on the rear of the chassis. Several hundred were produced before it was replaced by the M16 MGMC and M17 MGMC. 1,605 built.

M17 Half-track: M5 with the same quadruple 0.5 inch machine gun turret as the M16. All 1000 supplied to the USSR. It was mainly saw limited use at end of World War II and Korea.

M9 Half-track

The M9 Half-track was a half-track produced by International Harvester in the United States in World War II. It was designed to supersede the M2 Half Track Car which was mostly outclassed by 1942. Although the M2 had thicker armor than the M3 half-track it could be penetrated by AP rifle bullets from 300 yds rather than 200 yds for the M3. It had the same body and chassis as the M5 Half-track (also built by International Harvester) but had the same stowage and radio fit as the M2 Half Track.

The M9 served for a long time, and is still in service with Paraguay today. 3,500 were produced by the end of World War II. It was used during World War II, the Arab-Israeli War of 1948, the Korean War, the Suez Crisis, the Vietnam War, the Six-Day War, and the Yom Kippur War.

The M9 Half-track was built at a time when the M2 Half Track Car was outclassed and needed a good replacement for its job. So, the U.S. decided to make the same thing except based on the M5 Half-track (APC) but still had the stowage, access to the radios from the inside, rear doors, and a pedestal machine gun mount like the M2. The M9A1 also had a ring mount machine gun mount and three pintle machine gun mounts.

When the M9 started production in August 1942, it was produced by International Harvester instead of White Motor Company because it was based on the M5 Half-track, not the M2 Half Track Car. The M9 and M9A1 were produced en masse and 2,026 were produced in total.

The M9 served in: World War II, Arab-Israeli War of 1948, Korean War, Suez Crisis, and many others. All of the production half-tracks were leased to other countries, like most other International Harvester half-tracks produced in World War II. This time it was leased to both the Soviet Union and the British Commonwealth which leased it to other countries.

The M9 was used by many countries but not the United States as production (as with other half-tracks built on the same chassis by International Harvester) was for Lend-Lease and there was sufficient M2 and M3 production for U.S. needs. Britain leased some half-tracks to Free France and other governments that got expelled from their country by the Germans. The Soviet Union received supplies directly.

After the war they half-tracks were sent to the Military Aid Program.

M13 Half-track

The M13 Multiple Gun Motor Carriage (M13 MGMC) was a World War II self-propelled anti-aircraft gun produced by the White Motor Company when the United States needed a mobile anti-aircraft vehicle. Production commenced in July 1942 and ended in May 1943. The only time it was ever used was when the Americans landed at Anzio in January 1944. It was replaced by the better armed M16 Half-track in April 1944.

The M13 evolved from a series of unsuccessful prototypes that were trialed in the period from 1940 to 1942 until it finally started production. It turned out to be an interim solution as the better armed M16 MGMC arrived in 1944. Half of the M13 production were converted into M16s on the production lines.

The M13 Half-track was 6.50 m (21 ft 4 in) long, 2.16 m (7 ft 1 in) wide, 2.34 m (7 ft 8 in) high with a wheelbase of 135.5 in (3.44 m). It had leaf spring suspension for the wheels and vertical volute springs for the tracks. It had a 60 U.S. gal (230 l) fuel capacity and a 150 mi (240 km). The vehicle was powered by a White 160AX, 128 hp, 386 in3 (6,330 cc), 6 cylinder, gasoline engine, with a compression ratio of 6.3:1. It had a power to weight ratio of 15.8 hp per ton and weighed 9 tons. The armor across most of the vehicle was 0.25 inch (6 mm) thick with a 0.5 inch (12 mm) thick windscreen visor. The vehicle was armed with two M2 Browning heavy machine guns.

The first development version of the M13 was the T1, which had two M2 machine guns on a Bendix machine gun mount—as used on jeeps—mounted on an early version of the M2 Half Track Car. This early version was designed in 1940 and was just a prototype. Next came the T1E1 and T1E2 which were much the same, but the T1E2 had the M33 Maxson mount instead of the Bendix mount. (The T1E2 became the M16 Half-track by replacing the M33 with the M45 mount).

The T1E3 version came with a Glenn L. Martin Company turret, as used on bombers, with all of the electric systems included. As the last version of the M13, the T1E4 had the same armament as the T1E2 but used the longer hull of the M3 Half-track, which was accepted into production as the M13 Multiple Gun Motor Carriage on 27 July 1942.

With acceptance into production as the M13 Multiple Gun Motor Carriage, a total of 1,103 were produced from 27 July 1942 to 15 May 1943. Half of them (583) were converted into M16s before reaching the army.

The M13 served at the Battle of Anzio with the VI Corps of the Fifth United States Army in January 1944. It was used as an anti-aircraft support weapon during the landing at Anzio and then later to repel heavy German panzer attacks on the beachhead. It was replaced three months later by the M16 Half-track in April 1944. Only 139 were deployed overseas by the United States Army.

Variants

T1: Two M2 Browning heavy machine guns mounted on a Bendix mount on early model of a M2 Half Track Car. This model, like most of the others, was a prototype.

T1E1: A modified version of the T1E1. This was another prototype.

T1E2: Same as the T1E1 except the Bendix mount was replaced with the M33 Maxson mount. After the M33 was replaced with the M45 Quad mount it was accepted as the M16 Half-track.

T1E3: Replaced the M33 with a Martin turret designed for use on bombers.

T1E4/M13: The Martin turret was replaced by the M33 and was based on the M3 Half-track. It was accepted as the M13 Half-track in July 1942. Saw action at the Battle of Anzio to repel heavy German attacks. Replaced by the M16 in April 1944.

M14 Half-track: Same armament as the M13 but based on the M5 Half-track. Mostly supplied to Britain, where they were converted back to regular half-tracks.

M14 Half-track

The M14 Multiple Gun Motor Carriage was an self-propelled anti-aircraft artillery produced for the United States in World War II by International Harvester for Lend-Lease to Allies.

The M14 was a variant of the M13 Multiple Gun Motor Carriage based on the M5 Half-track (the M13 was based on the M3 Half-track). Both the M13 and M14 were supplanted by the M16 Half-track and M17 Multiple Gun Motor Carriage half-tracks which had four heavy machine guns in a M45 Quad mount to the M14’s two in a M33 Maxson mount.

Although intended for supply to the British under the Lend-Lease, it was not accepted as such and most were rebuilt as carriers.

In order to produce a light self-propelled anti-aircraft weapon, two 0.5 in (13 mm) M2 heavy machine guns in a M33 turret mount produced by Maxson were mounted on a M3 Half-track to produce the half-track M13 MGMC. The same turret mount when fitted to the M5 Half-track was designated the M14 half-track. These two were accepted for production in mid-1942. Several hundred were produced before the superior four machine gun M45 Quad mount Maxson mounting was accepted in late 1942 for production and this on a M3 gave the M16 MGMC half-track and on the M5 gave the M17 MGMC.

The entirety of M14 production was scheduled for delivery to the British but were not acceptable for their needs and “most” were rebuilt as carriers instead.

Like other half tracks the soldiers complained about overhead cover from bombs and artillery. But it served well as an low range support for infantry and as a low range anti-aircraft gun. They were leased to the United Kingdom. Most of them where rebuilt in Britain as carriers.

It was produced by International Harvester to be a version of the M13 Half-track. It was only leased in 1941 and 1942. International Harvester produced 1600 of them.

M15 Half-track

The M15 Half-track, officially designated M15 Combination Gun Motor Carriage, was a World War II United States Army self-propelled anti-aircraft gun on a half-track chassis. It was equipped with one automatic 37 millimeter (1.5 in) gun and two water-cooled 0.5 in (12.7 mm) M2 Browning heavy machine guns in a coaxial mount controlled by a M6 sighting system. It was produced by the White Motor Company between July 1942 and February 1944, and served alongside the M16 Multiple Gun Motor Carriage.

It evolved from the T28 project, initially as the T28E1 Combination Gun Motor Carriage (CGMC). It was accepted into service in 1943 as the M15, equipping U.S. Army armored units during the latter stages of World War II. The 37 mm gun was often used as an infantry support weapon. The M15A1 was an improved variant with air-cooled machine guns mounted below the 37 mm gun. The M15 “Special” was based on the M15 but produced to fulfill the same role by mounting a Bofors 40 mm gun.

During World War II, the vehicle served the U.S. Army throughout the Mediterranean, European, and Pacific Theaters of Operations. During the Korean War, the M15 served alongside the M16 providing support to the infantry.

The M15 was based on the M3 Half-track chassis – a vehicle built from commercial components to maximize production. The M15 was 20 ft 3 in long, 7 ft 4 in wide, and 7 ft 10 in high, with a wheelbase of 135.5 in (3.44 m). The suspension for the wheels was a leaf spring, while the track bogies had vertical volute springs. The M15 had a fuel capacity of 60 U.S. gallons}, which produced a range of 150 mi, and was powered by a White 160AX, 128 hp, 386 in3, 6-cylinder petrol engine with a compression ratio of 6.3:1, which produced a maximum road speed of 41.9 mph. It had a power-to-weight ratio of 15.8 hp per ton. Armament consisted of a fully automatic 37 mm (1.5 in) Gun M1 and two 0.50 cal M2 Browning machine guns mounted above the 37 mm gun. With up to 12 mm of armor it weighed 9.45 tons and had a crew of 7.

The M15 design developed from the T1A2 Multiple Gun Motor Carriage (MGMC) project, which was based on the M2 Half Track Car. With the addition of a 37 mm gun, this design became the T28. The T28 project was canceled in 1942 by the United States Army Coast Artillery Corps.

A United States Army Armored Force requirement for a mobile anti-aircraft gun to support the coming North African campaign resulted in the T28 project being revived soon after its cancellation. The new vehicles used an M3 Half-track chassis, and were designated as the T28E1 CGMC.

A total of 80 T28E1s were produced from July to August 1942, all of which had an unprotected mount for the gun combination and crew. Spotting targets was done with a M2E1 sighting system. After 80 T28E1s had been produced, the vehicle went into production with the designation M15 CGMC. Some of the T28E1s still in service were converted back into M3A1 Half-tracks.

The M15 was equipped with the M42 armored weapon mount, in which two water-cooled M2 Browning machine guns were mounted above the 37 mm gun. A total of 680 M15s were produced in 1943 but because the M42 mount placed considerable stress on the M3 chassis, the M54 mount was introduced, and the resulting combination with the M3A1 Half-track chassis was designated as the M15A1 CGMC. In August 1945, the M42 mount, and the M15 CGMC was finally classified as obsolete. The M54 gun mount reversed the places of the machine guns and 37 mm gun, and air-cooled M2 Browning machine guns replaced the water-cooled weapons used on the M15. Spotting targets was done with a M6 sighting system. A total of 1,052 M15A1s were produced in 1943, with a further 600 being produced in 1944. The unofficial name “M15 Special” relates to M15s and probably other CGMCs converted in depots in Australia to mount the Swedish-designed Bofors 40 mm gun on a half-track chassis. This was the only successful conversion of a U.S. half-track to mount the Bofors gun.

The M15 was first used during Operation Torch, the Allied invasion of North Africa in November, 1942. When engaging enemy aircraft, tracer ammunition from the machine guns was used to bring the main gun onto the target. T28E1 crews claimed more than 100 aircraft kills during Operation Torch, the Battle of Kasserine Pass, and the Allied Invasion of Sicily; 39 alone were claimed at Kasserine. One T28E1 was captured by the Germans at Kasserine Pass and was later rebuilt as a carrier for equipment and troops to replace German vehicles destroyed by Allied aircraft.

Each U.S. Army armored division was allocated an anti-aircraft artillery (AAA) company equipped with eight M15 CGMCs and eight M16 MGMCs (four Browning M2 machine guns). At corps and army level, each AAA battalion was equipped with 32 of each vehicle. After first seeing action in the Allied invasion of Italy, the M15 and M15A1 served through the rest of the Italian Campaign, the Allied invasion of Normandy and of southern France, and throughout the Western Front, including the Battle of the Bulge. They were often used in the ground support role, as Allied air superiority meant that there were few German aircraft left to engage. They were also used in the Pacific theater during the campaign to liberate the Philippines and the Battle of Okinawa. The “M15 Special” was used by the 209th AAA Battalion in the Philippines in 1944–45. The M15 and M15A1 also served in the ground-support role during the Korean War.

The proficiency of this mobile weapon can be attributed to three characteristics: its mobility, enabling to work well in close support of combat troops in forward areas and to patrol roads over which heavy traffic must travel under constant threat of bombing and strafing; its flexible firepower, combining the volume of caliber .50 with the knocking power of the 37 mm; and the facility which the fire is controlled, by using the tracer stream from the caliber .50 to bring it on target before opening up with the full volume of armament. Numerous cases are cited in which a “mouse trap” effect has been obtained which enemy planes came in much closer on the initial caliber .50 fire than they would on a light cannon and were caught by the 37 mm.

An army report from North Africa

M16 Half-track

The M16 Multiple Gun Motor Carriage was a self-propelled anti-aircraft weapon using a half-track chassis. It was used by the United States Army, the British Commonwealth, and South Korea. This vehicle replaced the M14 MGMC half-track in the anti-aircraft role and went on to serve during World War II after 1943 and the entire Korean War. The M16 was famous for downing low-flying aircraft and was nicknamed the “Meat Chopper” because it tore the aircraft’s fuselage to pieces with its machine guns and was extremely popular with soldiers.

The M16 was an improvement on the M13 MGMC and M14 MGMC which used twin 0.5 heavy machine guns in a Maxson M33 turret mounting on a M3 and M5 half-track chassis respectively. The two guns were increased to four giving the M45 Quad mount. Further production of the M13 and M14 was stopped so that resources could be used to produce the M16 and M17.

The M16 was extremely popular with most soldiers and many officers. Some soldiers nicknamed the M16 “The Meat Chopper.” In addition to its anti-aircraft role, the M16 could also be used to provide fire support to infantry on the ground, and was frequently employed in this role and was often accompanied by the M15 Half-track. The M16 was similar to related models like the M17 MGMC and some models based on the SdKfz 251 half-track used by Nazi Germany.

During World War II, the M16 was used by the United States Army in several campaigns including: Italy, Operation Overlord, the Battle of Arracourt, and the Ardennes Offensive. The vehicle was later also used in the Korean War by the South Korean Army, the United States Marines, and the United States Army, seeing action during the Battle of Pusan Perimeter, the Battle of Inchon, the First Battle of Seoul, the Battle of Pyongyang, the Second Battle of Seoul, and many others.

Variants

M16: The original version. It had four M2HB machine guns in the M45D Quad-mount.

M16A1: Almost exactly the same but directly converted from the M3 Half-track, and used the M45F Quad-mount.

M16A2: Original M16s brought up to M16A1 standard with a M45F Quad-mount.

M17 Half-Track: Same as the M16, built on the M5 Half-tracks and leased under the Lend Lease to the USSR. It still had the M45F Quad-mount.

M17 Half-track

The M17 Multiple Gun Motor Carriage was a U.S. self-propelled anti-aircraft weapon produced by International Harvester for Lend-Lease to the Allies during World War II. The M17 was a four-heavy machine gun mounting on a M5 Half-track chassis. International Harvester produced 400 M17 half-tracks in 1943 and 600 in 1944. All were provided to the Soviet Union in 1943 and 1944.

The first MGMC Half-tracks were the two-gun M13 and M14 based on the M3 and M5 half-track chassis respectively. When the two-gun mounting was improved to the Maxson M45 four-gun mounting this gave the M16 and M17. The M45 Quad mount was slightly different from earlier models of the M16. Later models of the M16 could interchange their quad mounts with the M17.

The M17 was accepted into production in 1943. All of them were shipped to the Soviet Union in late 1943 and early 1944.

The M17 was produced by International Harvester in the latter half of 1943 to the former half of 1944. Like most International Harvester produced half-tracks, all of the half-tracks were provided to the Allies - either the British Commonwealth, France, or the Soviet Union. This time it was the Soviet Union who got the half-tracks.

The M17 served with the Soviet Union from the latter half of 1943 until the end of World War II. A significant amount (up to half) of the Soviet’s air defense was made of M17 half-tracks. The M17 served through the Minsk Offensive, Battle of Smolensk (1943), Battle of the Baltic (1939-1945), Operation Bagration, and many others. It also served in the Korean War with the Chinese. The Soviet Union outclassed the M17 at the end of the Korean War.

M3 Gun Motor Carriage

The 75 mm Gun Motor Carriage M3 was a United States tank destroyer and self-propelled artillery piece of World War II. It was the most numerous tank destroyer in United States Army service during the critical battles in North Africa and the Philippines; and continued to be used in more limited numbers in Sicily, before being declared obsolete in early 1944. The GMC M3 was then used by the regimental weapons companies of Marine regiments in 1944–1945 at Saipan, Peleliu and Okinawa.

The German victory over France in 1940 using armored divisions profoundly impressed the United States Army. Realizing that defense against tanks was essential, an urgent requirement was issued for the development of tank destroyers for the U.S. Army. In June 1941, an M3 Half-track was mated with a 75 mm gun M1897A4, which was an American version of the famous “French 75” of World War I fame. This experimental vehicle was known as the T12, and proved to work remarkably well given the speed with which it was developed. Standardized in October 1941 as the 75 mm GMC M3, over 2,200 75 mm GMC M3s were produced until April 1943. However, a large number of them were converted back to standard half-tracks before issue to troop units, resulting in only 842 seeing field service. The GMC M3A1 was a variant that used a different gun mount. The 75 mm GMC M3 was reclassified first as limited standard and later, in 1944, as obsolete.

The 75 mm GMC M3 was an M3 Half-track with an M1897A4 75 mm gun mounted in the rear of the half-track. The gun had an indirect fire range of 9,200 yd (8,400 m), and fired the AP M72 (Armor Piercing) shell that could penetrate 3.2 in (8.1 cm) of armor at 500 yd (460 m), the APC M61 (Armor Piercing Capped) shell that could penetrate 2.8 in (7.1 cm) of armor at 500 yd, and the HE M48 (High Explosive) shell for use against infantry and other non-armored targets. The GMC M3 carried 59 rounds of 75 mm ammunition on board. The crewmen were equipped with a rifle and four carbines for self-defense.

Confronted with an impending war with Japan, 75 GMC M3s and T12s, termed “Self-Propelled Mount” (SPM) half-tracks, were shipped to the Philippine Islands in September 1941 to form the (2nd) Provisional SPM Brigade. These vehicles saw action during the Japanese invasion of the Philippines, and some were later captured by the Japanese and used against U.S. forces in 1944.

The GMC M3 was the most widely deployed tank destroyer in U.S. tank destroyer battalions during the campaign in Tunisia in late 1942 and early 1943, and was prominent during the battles of Sidi Bou Zid, Kasserine Pass, and El Guettar. Although many GMC M3s were lost in these battles, the U.S. Army concluded that improper employment had caused some of these losses. The GMC M3 was again used in the tank destroyer role in the Sicilian Campaign in July 1943. Subsequently, the GMC M3 was phased out of tank destroyer battalions and replaced by the GMC M10, a turreted tank destroyer mounting a modern 3 inch gun. Small numbers were used for specialized tasks, such as assault guns with the Rangers of Task Force Sugar in Brittany.

Although then considered obsolete for use against German tanks, the GMC M3 was powerful enough to destroy the light tanks deployed by the Japanese, and so the GMC M3 continued to be used in the Pacific Theater, primarily with regimental weapons companies of the United States Marine Corps, seeing action on Saipan, Peleliu, and Okinawa, among other island battles. Because tanks were not frequently deployed by the Japanese, the GMC M3 was often used as a self-propelled artillery piece or for direct fire support against Japanese fortifications. In 1945, the GMC M3 was replaced in Marine Corps use by the 105 mm HMC M7 self-propelled artillery piece.

Around 170 GMC M3s were provided to the British Army in early 1943. The British deployed them in the headquarters troops of armored car and tank units as self-propelled artillery pieces. These, known as 75 mm SP, Autocar in British nomenclature, were employed in Tunisia and Italy. The 75 mm GMC M3 was also used by the French Army on a limited basis on the Western Front 1944-45. The M3 GMC was also used by the Philippine Army and Philippine Constabulary during World War II under Japanese Occupation (1942-1945) and the post war era (1945-1960s) using Hukbalahap Rebellion by local government forces against Huk rebels and Korean War by PEFTOK.

Variants

T12/M3 GMC : M3 based Gun Motor Carriage equipped with the M1897A4 75 mm gun. In earlier models they left the M2A3 ground carriage and gun shield untouched. In later models they re-equipped it with the same gun with a purpose-built gun shield (59 rounds).

M3A1 GMC: Based on the original model. Replaced the M2A3 carriage with the M2A2 carriage. Later models include a purpose-built gun shield.

T19 Howitzer Motor Carriage

The T19 Gun Motor Carriage (HMC), was a World War II United States Army self-propelled gun mounted on a half-track chassis. It was equipped with a 105 mm (4.1 in) howitzer and an air-cooled .50 in (13 mm) caliber M2 machine gun mounted coaxially to the howitzer. It was produced by Diamond T between January 1942 to April 1942.

It served in the North African Campaign, while a couple served in the Sicilian Campaign, the Italian Campaign, and even as late as the Invasion of southern France.

The T19 Howitzer Gun Motor Carriage was similar to those of the M3 Half-track. The T19 was 20 ft 2 in long, 6 ft 5 in wide, 7 ft 8 in high, with a weight of 9.54 short tons. The suspension consisted of a semi-elliptical longitudinal leaf spring for the wheels and vertical volute springs for the tracks. Powered with a White 160AX, 147 hp, 386 in3, 6 cylinder petrol engine with a compression ratio of 6.3:1, it was capable of a maximum road speed of 45 mph. The power to weight ratio is 14.7 hp/ton. The vehicle is of operated by a crew of 6 with armor as thick as half an inch. The armament consisted of 1 105 mm M2A1 howitzer and a .50 caliber M2 Browning machine gun.

In the autumn of 1941, when the Armored Force expanded, an urgent need for self-propelled artillery arose. Although a full-track chassis were preferred, the situation required the use of whatever vehicles were immediately available. Once again, the job fell for the M3 half-track and it was selected to carry a 105 mm M2A1 howitzer. Although this design had originally been suggested in September 1941, it had been disapproved. However, the urgency of the requirement resulted in the approval by Adjutant General and the construction of a pilot was authorized by OCM 17391, dated 31 October 1941. This action designated the new vehicle as 105 mm howitzer motor carriage T19.

As with other American early-World War II self-propelled gun pilots it was assembled and tested at Aberdeen Proving Grounds, and used the M2 recoil mechanism and other parts of the M2 carriage. After several tests, the gun carriage proved fragile on bumpy terrain. The problem was corrected by reinforcing the frame, and redesigning the howitzer mount. Demountable headlights were recommended because of the muzzle blast, although they were unavailable for earlier production models. Earlier models had no shield for the howitzer but they later added a foldable shield during testing. The gun was facing forward, like many other half-track models. The total traverse was 40 degrees and the elevation was from +35 to -5 degrees. The armored windshield cover was remounted so it could fold onto the hood. After further testing, it was accepted for production.

After it was accepted, a pilot was shipped to Diamond T as a guide for production. The first production vehicle was delivered to the U.S. Army in January 1942. A total of 324 T19s were produced when production ended in April 1942.

The T19 HMC was designed as a stopgap measure until better self-propelled artillery pieces were made, it served in North Africa with a few serving in Sicily, Italy, and even as late as the Invasion of southern France (Operation Dragoon). It was retired after other pieces of self-propelled artillery were made (like the M7 Priest). It was finally declared obsolete by OCM 28557, dated 26 July 1945. That month the contractor Brown & McLaughlin converted 90 T19s into M3A1 Half-tracks.

T30 Howitzer Motor Carriage

The T30 Howitzer Motor Carriage (HMC) was a United States Army Self Propelled Gun used in World War II. It was based on requirements for an assault gun issued by the Armor Branch in 1941. It was simply a 75 mm Pack Howitzer M1 in an armored box mounted on a M3 Half-track. The fuel tanks were moved to the back of the M3 Half-track. It debuted in the North African Campaign in November 1942. Some were leased to Free French forces and the type was used as late as the First Indochina War in 1951.

The specifications of the T30 were similar to the specifications of the M3 Half-track. The dimensions were 6.28 m (20 ft 7 in) long, 1.96 m (6 ft 5 in) wide, and 2.51 m (8 ft 3 in) high, and the weight was 20,500 lb (9.3 t). The suspension consisted of vertical volute springs for the tracks and leaf springs for the wheels, with a fuel capacity of 60 U.S. gal (230 l). It had a range of 150 mi (240 km) and had a speed of 40 mph (64 km/h). Powered by a White 160AX, 147 hp (110 kW), 386 in3 (6,330 cc), 6-cylinder, gasoline/petrol engine, with a compression ratio of 6.3:1 it had a power-to-weight ratio of 15.8 hp/ton.

The design overall of the T30 was the same as the M3 Half-track but the difference was the gun. The 75 mm M1 Pack howitzer that was mounted could depress 9 degrees, elevate 50 degrees, and traverse 22.5 degrees to each side. The vehicle had stowage for 60 rounds of 75 mm ammunition, and although it was not designed for anti-tank use, it had a high explosive anti-tank (HEAT) shell that could penetrate 3 in of armor at normal ranging. The gun shield had 0.375 inch armor, designed to stop a .30 cal bullet from 250 yds away.

The T30 HMC was originally conceived in 1941 by the Armor Branch as an assault gun to equip tank and armored reconnaissance units. As a satisfactory design was close to a year away, the Ordnance Department decided to make an alternative design based on the M3 Half-track. The pilot vehicle came off the production lines in October 1941 armed with an M1A1 75 mm Pack Howitzer and its mounting design to fit a simple box mount on an M3 Half-track. It was authorized for production in January 1942, while the first deliveries to the Army came one month later. It was never type classified because it was viewed as a temporary solution. In September 1942 the T30 was partially replaced by the M8 HMC. After that it was declared as substitute standard. Around 500 were produced.

The T30 HMC entered service in November 1942. In one encounter, the T30 was used in an attempt to destroy German tanks. Although the T30s fired several volleys, the German tanks were barely damaged; as a result, the Army learned that low-velocity howitzers were ineffective against most tanks. In the 1st Armored Division, each regiment was issued 12 T30s. Of these, three were used in each headquarters platoon and three were used in each regimental reconnaissance platoon. The 6th and 41st Armored Infantry Regiments were also issued nine T30s apiece, with three in the HQ platoon of each battalion. Infantry divisions in North Africa deployed a cannon company with six T30s and two T19 105 mm HMCs. The T30 also served during the Allied invasion of Sicily in 1943 and the 1944 Allied invasion of Italy. It was removed from infantry division use in March 1943 because of the reconstruction of infantry battalions. The T30 was eventually replaced by the M8 HMC which was based on the M5 Stuart light tank. Deliveries of the M8 began in November 1942. Only 312 T30 HMCs were delivered in their original configuration, as the last 188 were converted back into M3 Half-tracks before they were delivered. Later on, the U.S. leased several to Free French forces and some were used as late as the First Indochina War.

T48 Gun Motor Carriage

The T48 57 mm Gun Motor Carriage was a self-propelled anti-tank gun produced by the Diamond T company in 1943 by the United States. The design was a 57 mm gun M1 (U.S. production of a British design) mounted on a M3 Half-track. It was built when there was a requirement for a light, mobile self-propelled gun that could have a high rate of fire and could at least damage, if not knock out most tanks. A total of 962 vehicles were produced from 1943 to 1945. Of these, 652 were provided under Lend-Lease to the Soviet Union and 60 to Britain while the remainder served with U.S. forces. It served during Operation Bagration, Operation Overlord, the invasion of southern France, the Battle of the Bulge and the Western Allied invasion of Germany. Some of them were converted back to half-tracks.

Originally it had been planned that Britain would receive all of the examples produced, intending to use them in the Western Desert, but by the time they arrived the campaign was over. As a result, the British transferred all the half-tracks to the Soviet Union under the Soviet Aid Program. The Soviets called it the SU-57.

The T48 Gun Motor Carriage was 21 ft long (6.40 m), 7 ft 1 in (2.16 m) wide, 7 ft (2.13 m) high with a wheelbase of 135.5 in (3.44 m), and weighing 9.45 tons (20,800 lb). The suspension consisted of a leaf spring for the wheels and the front tread had Vertical Volute springs. The vehicle had a maximum speed of 45 mph (72 km/h). With a fuel capacity of 60 U.S. gallons (230 l), it had a range of 150 miles (240 km), and was powered by a 128 hp (95 kW) White 160AX, 386 in3 (6,330 cc), 6 cylinder, petrol engine with a compression ratio of 6:3:1. The power to weight ratio was 15.8 hp/ton. It also had 6–12 mm of armor, was armed with a single 57 mm Gun M1, and had a crew of three.

The T48 originated from a British and American requirement for a self-propelled 6-pounder anti-tank gun. The American requirement was dropped later. It was made by emplacing a 57 mm gun M1 – the U.S. production version of the British 6-pounder – in the rear of a M3 Half-track.

The pilot model was built at the Aberdeen Proving Ground in May 1942. The 57 mm Gun M1 was mounted in the M12 recoil mechanism and installed on a tubular pedestal. The tubular pedestal was soon replaced with a conical structure and was designated the 57 mm gun mount T5. The gun on the pilot model had a traverse of 27.5 degrees in both directions (total of 55 degrees), while having an elevation of +15 to -5 degrees. The short barreled British Mark III 6 pounder gun was installed in the pilot, but the longer barreled 57 mm Gun M1 was specified for the production models. The original travel lock for the recoil mechanism proved to be unsatisfactory, which was replaced by a travel lock on the front hood. The original design had a gun shield from the T44 57 mm Gun Motor Carriage. After the first tests were complete, a new shield was designed with 5/8 inches thick of face-hardened steel on the front and 1/4 inch thick on the sides and top. The shield extended over the crew with a relatively low silhouette of only 90 inches. Because of the experience from the M3 Gun Motor Carriage demountable headlights were mounted to avoid deformation of the hood. The deformation of the hood was caused by the muzzle velocity of the 57 mm gun. The T48 was accepted for production in 1942.

The British ordered all of the T48s that were produced, intending to use them in the Western Desert Campaign, but by the time they arrived the British had already won the war in the Western Desert and the appearance of the 75 mm gun, and later the Ordnance QF 17-pounder gun, meant that the T48 was surplus to British requirements. As a result, it was almost immediately shipped to the Soviet Union under the terms of the Soviet Aid Program. Through this program, the Soviets accepted 650 vehicles, adopting the designation SU-57. A small number were later passed to the Polish People’s Army.

Britain accepted 31 converting them back to carriers. The U.S. retained 281 vehicles which were also converted back to M3A1 standard carriers in 1944. They were converted by the Chester Tank Depot.

It served during Operation Dragoon, Operation Overlord, the Battle of the Bulge, Operation Bagration, and the much of the fighting that took place on the Eastern Front. It was retired immediately after the war because the 57 mm gun was no longer effective against most of the tanks that were then in service, making it obsolete.

Car, Half-track, M2, left side view.

Car, Half-track, M2, right side view.

Car, Half-track, M2, plan view (additional sketch at top shows an alternate roller).

Car, Half-track, M2, front view.

Carrier, Mortar, 81mm, M4 right side view.

Carrier, Mortar, 81mm, M4 left side view.

Carrier, Mortar, 81mm, M4 plan view (additional sketch at top shows an alternate roller).

Half-track Car M9A1 side view.

Half-track Car M9A1 plan.

Half-track Car M9A1 rear and front.

Carrier, Motor, Multiple Gun, M16 left side view.

Carrier, Motor, Multiple Gun, M16 plan view.

Carriage, Motor, 75mm Gun, M3A1 right side view.

Carriage, Motor, 75mm Gun, M3A1 left side view.

Carriage, Motor, 75mm Gun, M3A1 plan view.

Carriage, Motor, 75mm Gun, M3A1 front view.

Carriage, Motor, 75mm Gun, M3A1 rear view.

M9/M9A1 Half-track.

75mm Gun Motor Carriage M3.

Half-track Car T1.

Tracteur Citroen-Kégresse P.17 (with Canon de 75) as evaluated by the U.S. Ordnance Department in 1931.

 
Half-Track Car T1E1 (M1).

Half-Track Car T1E3 with modified suspension.

Half-Track Truck T1, 1933.

Half-track T1E3, Machine Gun Troop, 1st Cavalry (Mechanized), Fort Leavenworth, Kansas, 23 April 1934.

Half-Track Truck T3, 1933, was a Linn WD-12 commercial type half-track bought in small numbers as a heavy artillery tractor.

Half-Track Truck T5; 24 purchased in 1935 as artillery tractors.

Half-Track Truck T8 was a Ford truck with Trackson patent cable and chain half-track conversion sets for the rear wheels, tested only.

Half-Track Truck T9 with Cunningham Kégresse-type bogie was standardized as Half-Track Truck M2.

Half-Track Truck T9E1 was an experimental variant of the Half-Track Truck T9 fitted with light tank type bogies and track to test against the Kégresse-type bogies of the T9.

The Scout Car M2, built by White provided the body and chassis layout from which the armored half-tracks were developed.

Half-Track Personnel Carrier T7.

Half-Track Scout Car T14, prototype for the M2 Half-track, 1940.

Half-Track Car M2 without winch (note front roller).

Half-Track Car M2 with winch, large headlights and no side racks.

Half-Track Personnel Carrier M3 with winch, canvas top in place, small headlights and side racks.

Half-Track Personnel Carrier M3. All stowage compartments on this half-track are open. The seats have stowage under them, as well as the floor. The vehicle’s fuel tanks are near the front, and a .30 cal. machine gun is mounted on its pedestal. Rifle clips are also visible around the edge of the passenger compartment. This vehicle is fitted with the small, demountable headlights.

Half-Track Car M2A1 with .50-caliber and .30 caliber machine guns mounted and vehicle fully equipped.

Half-Track Personnel Carrier M3A1 with winch and all equipment stowed.

Half-Track Personnel Carrier M3A1 with winch and .30-caliber and .50-caliber machine guns mounted.

Half-Track Car T29 with under chassis heater equipment on side of cab, which was tested on this vehicle.

Half-Track Car M3A2 pilot model, fully equipped.

Half-Track Car M3A2 pilot model, fully equipped.

Half-Track Car M3A2 pilot model, fully equipped.

Half-Track Personnel Carrier M5 without winch, armament or equipment.

Half-Track Car M5A2 (T31) fully equipped.

Half-Track Personnel Carrier M5A1 without winch, fully equipped.

Half-Track Personnel Carrier M5A1 without winch, fully equipped.

Half-Track Personnel Carrier M5A1 without winch, fully equipped.

Half-Track Car M9A1 with winch and fully equipped.

Half-Track Car M9A1 with winch and fully equipped.

81mm Mortar Carrier M4 with mortar at lowest elevation.

81mm Mortar Carrier M4 with rear door closed and mortar at lowest elevation.

81mm Mortar Carrier M4 from rear showing mortar, bomb stowage, seats and fuel tanks.

81mm Mortar Carrier M4A1 fully equipped.

81mm Mortar Carrier M4A1 fully equipped and with full crew.

81mm Mortar Carrier M21, fully equipped.

81mm Mortar Carrier M21, fully equipped.

4.2-inch Mortar Carrier T21.

Half-Track Car T16 with roof in closed position and modified suspension.

Half-Track Car T16 with roof in open position.

Half-Track Truck T3, basic chassis adapted for use with the 40mm Gun Motor Carriage T1.

40mm Gun Motor Carriage T1.

40mm Gun Motor Carriage T54.
40mm Gun Motor Carriage T54E1.

Multiple Gun Motor Carriage T60.

Multiple Gun Motor Carriage T60E1.

40mm Gun Motor Carriage T68.

Half-Track Truck T3 with normal armored superstructure.

Half-Track Instrument Carrier T18.

Half-Track Truck T16.

Half-Track Truck T17.

Half-Track Truck T19.

General Patton’s personal command vehicle in North Africa with armored roof, side skirts and extra radio equipment. Note divisional and command (two-star general) metal flags on the fenders. This was typical of command car conversions. (US Army)

4.2-inch Mortar Carrier T21.

Half-track Personnel Carrier M3. Details of the rear suspension are visible in this picture. This vehicle is fitted with the double-coil spring-loaded idler wheel.

Track, standard for all vehicles.

Track chain, used on ice or mud, was supplied to each vehicle.

Front axle, disassembled.

Instrument panel for White/Autocar/Diamond T vehicles.

Experimental Mine Exploder conversion of Half-Track M3 with flail attachment.

M5 Half-Track (International Harvester) interior. A: forward tarp mount. B: right fuel tank. C: pintle mount for machine gun. D: middle tarp mount. E: forward handle. F: front floor plate. G: rifle rack. H: rifle rack. I: forward stowage compartment. J: rear handles. K: center stowage compartment. L: rear tarp mount M: rear rifle rack. N: rear stowage compartment (right). O: rear left rifle rack. P: rear handles. Q: seat backrest. R: seat cushion. S: rifle rack. T: mounting point. U: forward seat backrest. V: left fuel tank. W: attachment point. X: forward attachment point.

M9A1 Half-Track (International Harvester) interior. A: M49 ring mount. B: ring mount support attachment. C: ring mount support. E: machine gun pintle mount. F: seat backrest. G: cushion. H: handle. I: side handle. J: right fuel tank. K: floor board. L: right stowage frame. M: left stowage frame. N: left handle. O: left fuel tank. P: bazooka attachment. Q: attachment lug. R: seat backrest. S: forward attachment assembly. T: left stowage bin.

All eyes on the sky as an enemy air patrol is spotted, Italy 1944. Note M1919 Browning .30 cal. and .50 cal. machine guns on this M3.

Multiple Gun Motor Carriage T1E3.

Half-Track M3 armored ambulance evacuating wounded near front line, Echtz, December 1944.

Multiple Gun Motor Carriage T1E1.

Multiple Gun Motor Carriage T1E2 with superstructure sides removed.

Multiple Gun Motor Carriage T1E4 standardized as the Multiple Gun Motor Carriage M13.

Multiple Gun Motor Carriage M14.

Multiple Gun Motor Carriage T28, March 1941.

Multiple Gun Motor Carriage M15 production vehicle. The combination gun mount M42 formed an imposing structure on the rear of the MGMC M15.

Multiple Gun Motor Carriage T28E1, July 1942.

M15 Multiple Gun Motor Carriage (GMC), top view. The M15 had an armored enclosure on the rear that housed a 37mm M1A2 automatic cannon plus two .50 cal. M2HB machine guns. On the M15 the machine guns were mounted above the 37mm gun, while on the M15A1 the machine guns were below.

Multiple Gun Motor Carriage M15A1.

Multiple Gun Motor Carriage T37E1.

Multiple Gun Motor Carriage T37E1.

Multiple Gun Motor Carriage T58. Vehicle was originally used as T1E2 with earlier armament and was still marked as such when photo was taken.

Multiple Gun Motor Carriage M16.

Multiple Gun Motor Carriage M16.

Carrier, 81mm Mortar, Half-track, M4A1, 2nd Armored Division, in action near Amonines, Belgium, December 1944.

Multiple Gun Motor Carriage M16 in winter camouflage, December 1944.

75mm Gun Motor Carriage T12.

75mm Gun Motor Carriage M3.

75mm Gun Motor Carriage T73.

105mm Howitzer Motor Carriage T19. Pilot model as originally produced without shield.

105mm Howitzer Motor Carriage T19. Pilot model with production type shield fitted.

105mm Howitzer Motor Carriage T19E1 converted from T19 pilot model.

Half-track in British service employed as an armored ambulance. The canvas cover is fastened down and marked with the red cross on sides and top. Of interest is the specified red cross flag flying from the front of the cab. All ambulance vehicles in combat areas were supposed to carry this in accordance with the Geneva Convention. These armored ambulances were attached to tank battalions for casualty evacuation under fire.

75mm Howitzer Motor Carriage T30. First pilot model lacking shield.

75mm Howitzer Motor Carriage T30. First pilot model with original design of shield fitted.

75mm Howitzer Motor Carriage T30. Second pilot model with revised lower height shield.

Half-track M3 of the U.S. Army in Tunisia carrying a 37mm anti-tank gun, a typical field modification.

Half-track M2 in Oran with 37mm anti-tank gun in extemporized mount.

Though of poor quality, this view of a M2A1 in Italy shows a typical improvisation — twin .50 cal. machine guns on a raised mount, with a piece of AFV armored plate as a shield.

Another improvisation — a 75mm Pack Howitzer on a field carriage (less its wheels) arranged to fire from the rear door of a Half-track M3.

Half-track Personnel Carrier M9A1 as supplied to the British Army, 1944-45. This winch-fitted vehicle is shown with the canvas weather cover in place, fitting over the pulpit. British designation: Truck 15 cwt Half-track M9.

Half-track M2 of the French Morocan Division towing a 57mm anti-tank gun at the Volturno River, Italy, January 1944. Note the gun armor shields carried on the half-track.

Half-track M3 of the 8th Army towing a 17 pdr anti-tank gun at the Gothic Line, September 1944.

Lend-Lease Multiple Gun Motor Carriage M17 with Soviet troops.

75mm Gun Motor Carriage M3 in service with the Red Army under Lend-Lease, 1944.

Multiple Gun Motor Carriage T10.

Twin 20mm Gun Motor Carriage T10E1.

M16 multiple gun motor carriage half-track, right, and M15 Special gun motor carriage (field modification which replaced the 37mm gun/.50-cal. machine guns with a 40mm Bofors gun), left, 209th Anti-Aircraft Artillery Battalion, supporting the 32nd Infantry Division, Villa Verde Trail, Philippines, August 1945.

M16 MGMC half-track, 209th Anti-Aircraft Artillery Battalion, supporting M4 medium tanks, 754th Tank Battalion, near Kiangan, Luzon, 13 July 1945.

M16 Gun Motor Carriage being used for direct fire, Villa Verde Trail, Luzon, Philippine Islands, 1945.

81mm Mortar Carrier M4A1, armed with .30 cal. machine gun, with demountable fender headlights, which are demounted.

The rear door is open on this 81mm Mortar Carrier M4, but the skate rail would obviously make entry and exit from the rear door somewhat difficult. More mortar bombs were stowed just behind the usual side ammunition compartments, and these racks can be glimpsed at the side of the passenger compartment.

A look into the interior reveals the rearward-firing mortar and extra stowage for its ammunition. Seats for the crew flank the mortar, and a rear door has been added. Note the .50 cal. machine gun, which would be an easy substitution or addition to the specified .30 cal. machine gun.

The machine gun mounts M35 and M35C are shown on the left and right, respectively. These allowed the machine gun to be moved along the rail, as well as be elevated and traversed in the mounts themselves. Traverse in the mounts was restricted to 160° (80° left and right), but the rail ensured 360° coverage.

This 81mm Mortar Carrier M4 has the older fender-mounted headlights and is armed with a .30 cal. machine gun.

The three crew seats positioned around the mortar are visible in this picture, as well as details of the mortar mount without the ordnance present. Note that the hinged rear platform is present.

The floor stowage compartments on this 81mm Mortar Carrier M4A1 are open. Bows for the canvas cover are stowed on top of the rear stowage boxes, a machine gun tripod is on top of the right-hand box, and bedrolls for the crew are strapped to the rear of the boxes.

Field Marshal Erwin Rommel (saluting with marshal's baton) and Lieutenant Colonel Fritz Bayerlein, standing in a car, driving past motorized troops, including soldiers in a captured American M3 half-track (Personnel Carrier). Tunis, North Africa, 1942. (Bundesarchiv Bild 146-1990-071-31)

M3 75mm GMC in the surf on Bougainville, Solomon Islands. November 1943. (US Army)

A partly-finished [half-track] scout car body is lowered on a chassis in an Eastern war plant which formerly produced locks and safes. Diebold Safe and Lock Company, Canton, Ohio. December 1941. (Library of Congress's Prints and Photographs ID fsa.8b07994)

Partly finished halftrack scout cars travel along a moving assembly line in a plant converted from the manufacture of safes and locks. The bodies are made in this plant and mounted on chassis produced in a converted automobile plant. Diebold Safe and Lock Company, Canton, Ohio. December 1941. (Library of Congress's Prints and Photographs ID fsa.8b07996)

Partly finished halftrack scout cars travel along a moving assembly line in a plant converted from the manufacture of safes and locks. The bodies are made in this plant and mounted on chassis produced in a converted automobile plant. Diebold Safe and Lock Company, Canton, Ohio. December 1941. (Library of Congress's Prints and Photographs ID fsa.8b07995)

A column of halftrack armored cars waits for orders to proceed to a practice engagement at Fort Knox, Kentucky, June 1942. (National Archives Identifier (NAID) 196277)

A 1st Infantry Division half-track plows its way through a muddy road in the Hürtgen Forest. 16th Infantry Regiment, 1st Infantry Division. 15 February 1945. (US Army)

M15 37mm/.50 cal. Multiple Gun Motor Carriage, “Brass City,” being loaded onto an LCT during pre-invasion loading in an English ort, late May or early June 1944. (US Army)

War Correspondent Ted Stanford of The Pittsburgh Courier, a weekly, interviews 1st Sgt. Morris O. Harris, tank man of the 784th Tank Battalion operating with the Ninth Army. March 28, 1945. (National Archives Identifier (NAID) 535535)

M21 81mm Mortar Carrier at tests, 28 April 1944. (US Army)

An M3 Gun Motor Carriage rolling out of an LST and onto Cape Gloucester in 1943. (US Army)

A partially built M3 half-track at the White Motor Company factory.

Armored personnel carrier half-track, 46th Armored Infantry Battalion, 5th U.S. Armored Division in Wittenmoor, Germany, April 1945. Note racks on sides filled with ammunition boxes and crates. The vehicle is fitted with a winch hidden under the tarpaulins, boxes and chains on the front of the vehicle. (US Army)

‘Acorn Inn,’ a self-propelled 75mm gun M3 half-track of 27th Lancers, north-west of Mezzano, 18 February 1945. (Imperial War Museum)

An M15 on Okinawa. (US Army)

M3 halftrack.

T19 prototype of the M21 Half-track Mortar Carrier, an upgrade and replacement for the M4 and M4A1 Half-track Mortar Carrier.

75mm Gun Motor Carriage M3.

75mm Gun Motor Carriage M3.

International M9A1 Half-track, 1943.

M9A1 Half-track.

M2 Half-track during field test.

M2 Half-track, 67th Armored Regiment, Sicily.

M2 Half-track Car.

White M3A1 Half-track Personnel Carrier.

White M3 Half-track.

M3A1 Half-track towing 105mm M2A1 Howitzer through Zweibriucken during the Seventh US Army advance into Germany, March 1945.

M3A1 Half track with trailer, 3rd Division, Strasskirchen, Germany.

A M3 Personnel Carrier, on the right, had been used by 10.(Pi.)/Pz gren Rgt 111, 11.Pz.Div since December 1944. Gepanzerter Mannschaftstransportwagen M3 401(a) is modified with four pivoting mounts for Wurfrahmen 40; Schwarzbach, Czech/Austrian border, 7 May 1945.

Cropped portion of the previous photograph showing the modified M3 half-track.

A view of the right side of the same modified half-track.

Another view of the scene; the half-track can just be seen in the middle of the photograph parked next to a German truck.

Captured M3 half-track in German service marked as an ambulance, North Africa.

57mm Gun Motor Carriage T48.

M17 MGMC half-tracks in Soviet service.

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