World War 2 In Review: 04/09/25

T7 Light Tank/M7 Medium Tank

M7 Medium Tank produced at International Harvester's Bettendorf Works. Only seven of these tanks were ever delivered to the military. 1942.

The Medium Tank M7 was originally conceived as an up-gunned replacement for the Light Tank M3/M5. The project was supposed to mount the same 75mm armament as the M4 Sherman while retaining the light weight and maneuverability of the M3 Stuart; however, during development the weight of the prototype surpassed the US Army's standard for light tanks and crossed into the medium category. The M7 had significantly less armor than the M4 Sherman, boasted no greater firepower, and held only a slight advantage in top speed. For these reasons, and because the M4 was already battle-tested and in full production, the M7 was put aside shortly after completing trials.

On January 1941, the Armored force prepared a list of characteristics for a new light tank. It was assigned the designation T7. During the development program, its weight increased from 14 to almost 27 tons. A more apt classification was thus given by OCM 18522, dated 6 August 1942, which standardized the T7E5 as the M7 medium.

Test revealed that the produced vehicles were heavier than anticipated at 28 to 29 tons fully stowed. This reduced performance and production was halted until it could be rectified. Analysis of the problem indicated that it was caused by castings being thicker than specified. Six of the production tanks were then modified to use the lightest castings possible and their power trains were revised to improve performance. The modified vehicles were referred to as M7E2s in some documents. Testing of the modified vehicles revealed improved performance but only at lower speeds and that the performance was considered inferior to the M4A3 medium tank. The 6 modified vehicles and the remaining 7 were accepted as M7 mediums bringing the total run to 13 tanks. Thus production acceptance records show only a total of 7 tanks.

Specifications

Type: Medium tank

Place of origin: United States

Manufacturer: International Harvester Corp.

Produced: 1942

Number built: 7

Weight: 53,950 lb (24,470 kg)

Length: 17 ft 2 in (5.23 m)

Width: 9 ft 4 in (2.84 m)

Height: 7 ft 9 in (2.36 m)

Crew: 5 (Commander, loader, gunner, driver, co-driver)

Armor: 13–64 mm (0.51–2.52 in)

Main armament: 75 mm M3 in M47 mount; 71 rounds

Secondary armament: 3 × .30-06 Browning M1919A4 MG; 4,500 rounds

Engine: Continental R975-C1; 9 cylinder, 4 cycle, radial gasoline; 350 hp (260 kW)

Suspension: Vertical volute spring

Speed: 30 mph (48 km/h) on road

Variants

T7: Welded hull, five speed Hydramatic transmission, volute spring suspension

T7E1: Riveted hull, formed homogenous plate turret, torque converter

T7E2: Cast upper hull, Wright R-975 Engine, Warner Gear torque converter, armed with Ordnance QF 6-pounder Mark III

T7E3: Welded hull and turret, twin Hercules DRXBS diesel engines, Detroit Gear automatic transmission

T7E4: Welded hull and turret, twin Cadillac engines, two Hydramatic transmissions

T7E5: T7E2 rearmed with 75 mm M3 standardized as M7 medium

M7 Medium Tank.

Partially assembled and completed M7 Medium Tanks at International Harvester's Bettendorf Works. 22 March 1943.

Partially assembled M7 Medium Tanks at International Harvester's Bettendorf Works, 22 March 1943.

Partially assembled M7 Medium Tanks at International Harvester's Bettendorf Works. 22 March 1943.

M7 Medium Tanks in storage on the shipping dock at International Harvester's Bettendorf Works. 22 March 1943.

Interior of the tank arsenal at International Harvester's Bettendorf Works. 29 June 1942.

M7 Medium Tanks built by International Harvester for the U.S. military. The tanks were produced at the Quad-Cities tank arsenal at International Harvester's Bettendorf Works. 1943.

The T7E2 Light Tank, still armed with the 57mm gun.

T7E2 Light Tank.

M7 Medium Tank.

T7E1 Light Tank with turret from M3 Medium Tank.

Mockup of T7E1 Light Tank with turret from M3 Medium Tank.

T7E1 Light Tank with turret from M3 Medium Tank.

T7E1 Light Tank with turret from M3 Medium Tank with drive train exposed.

T7E1 Light Tank with turret from M3 Medium Tank with engine exposed.

Comparison of side views of T7E1 Light Tank and mockup of T7E2 Light Tank.

Comparison of front views of T7E2 Light Tank and T7E1 Light Tank.

T7E2 Light Tank.

M7 Medium Tank upper view with hatches opened.

M7 Medium Tank upper view with hatches closed.

Rear view of M7 Medium Tank.

M7 Medium Tank.

M7 Medium Tank right front view.

M7 Medium Tank left rear view.

M7 Medium Tank top view.

M6 Gun Motor Carriage

As an addition to the battalion's defense, HQ Co. of the 5th Armored Maintenance Bn. developed an idea thought up by Ordnance Sgt. Magazine. The 37mm anti-tank gun is the only field weapon allotted for the battalion's defense. To increase firepower, a .50 cal. machine gun was mounted on the front of the 37mm Gun Motor Carriage M6. All parts were made and mounted by HQ personnel. 6 June 1943, Second Army Tennessee Maneuvers, 3 miles west of Watertown.

The 37 mm Gun Motor Carriage M6 (also known as M6 Fargo, and under the manufacturer's designation WC55) was a modified Dodge WC52 light truck mounting a light anti-tank gun. It was used by the United States Army for infantry support and as a mobile anti-tank gun. It operated from late 1942 to January 1945 in the Mediterranean, European, and Pacific theaters of World War II. The M6 saw limited use during the war, and was poorly suited to modern warfare as it was unarmored and was armed with a too small caliber gun.

The 37 mm GMC M6 was a modified 3/4-ton 4x4 Dodge WC52 truck with a rear-facing 37 mm M3 gun mounted in its bed (portee) and designated WC55. The gun was normally fired to the rear — it could not be fully depressed when pointed to the front of the vehicle due to blast effects on the crew and vehicle windshield. The gun fired M74 Armor Piercing (AP) Shot that could penetrate 1.4 in (3.6 cm) of armor at 500 yd (460 m). Other ammunition carried throughout its service life included the Armor Piercing Capped (APC) M51 Projectile (which could penetrate 2.4 in (6.1 cm) of armor at 500 yd), and the High Explosive (HE) M63 Projectile. Eighty rounds of 37 mm ammunition were carried aboard.

The crew members were equipped with personal weapons for self-defense.

With the design standardized in February 1942, 5,380 GMC 37 mm M6 GMC were built between April and October, 1942, at a cost of $4,265 per unit. American doctrine planned for tank destroyers to engage enemy tanks while tanks were used principally to support infantry. The 37 mm GMC M6 saw limited employment with U.S. forces (the 601st and 701st Tank Destroyer Battalions) during the campaign in Tunisia in late 1942 and early 1943. The vehicle was not well liked because it lacked armor and carried an anti-tank gun that was largely ineffective against German tanks of the period. The 37 mm GMC M6 also saw limited use in the Pacific Theater in 1943 and 1944. The 37 mm GMC M6 was soon classified as "limited standard" in September 1943, because of the availability of more powerful tank destroyers mounting 75 mm (2.95 in) and 3 in (76 mm) guns. In January 1945, the GMC M6 was declared obsolete.

After the Tunisian campaign, many M6 Fargos had their 37 mm gun removed and reverted to a cargo truck role as the (WC52). Some of these 37 mm guns were mounted onto halftracks to provide the armored infantry with a gun halftrack. Other 37 mm GMC M6 vehicles found their way into service with the French Army, and were later provided to French Forces of the Interior units after the liberation of France. Despite the vehicle's obvious limitations on the battlefields of Northwest Europe 1944–1945, the FFI used practically any vehicle they could obtain because of equipment shortages of all kinds.

Specifications

Type: Tank destroyer

Place of origin: United States

In service: 1942–1945

Used by:

United States

Free France

Philippine Commonwealth

Wars: World War II

Weight: 7,350 lb (3,330 kg)

Length: 14 ft 10 in (4.52 m)

Width: 7 ft 4 in (2.24 m)