M3 Medium Tank vs Panzer III

The M3

The US Army did not possess a medium tank in the 1930s, although several developmental designs existed on paper, and in some cases, prototypes were built through the 1920s. These exhibited British influence and bore small-caliber, low-velocity guns. In May 1936 the Army’s Ordnance Committee directed the development of a new tank based on Infantry Board requirements. Designated the T5, the projected medium tank was an enlarged M2 light tank, the predecessor of the M3 and M5 Stuarts. Some M2 components were used in the T5, but the new tank was to have heavier armor and armament. The T5’s armament was little different than on its light counterpart. It was envisioned as an infantry support tank and not for tank-to-tank combat.

The T5’s chassis was not unlike the future M3’s. The front glacis was well sloped, but the superstructure’s sides and rear were vertical and further made vulnerable by numerous vision/pistol ports. The centerline driver’s position had large shuttered ports to the front and sides. The high, boxy superstructure mounted a cramped centerline turret with the new 37mm M3 high-velocity gun. A .30cal machine gun in each of the four corner sponsons provided 360-degree defense. On either side of the turret and between the sponsons were manholes mounting a .30cal for antiaircraft, which had to be dismounted to allow the turret to traverse. Two fixed forward-firing machine guns were fitted in the glacis near the track guard fenders. It lacked a coaxial machine gun, but bristling with eight, that was not a real deficiency. The five-man crewed tank had a high profile, a characteristic that would plague US tanks for years. Its armor was comparatively heavy for the era, the lower front being 1.125in. and the vertical sides 1.25in.

The 1937 T5 Phase 1 prototype was fitted with a wooden mock-up superstructure, and various armament arrangements were tested. The Phase 2 was a never-built concept study. The Phase 3, after trying out further armament arrangements, was standardized as the M2 medium tank in summer 1938. The T4E2 had only a machine gun turret and a much-modified glacis, with the driver’s station moved to the left and a 75mm M1A1 pack howitzer mounted in the right front. This concept would be used in the M3.

With a major war in Europe, the first of 18 M2 medium tanks rolled out of the Rock Island Arsenal in Illinois in early 1940. The M2A1 was soon approved, featuring a redesigned turret, a more powerful engine, and other improvements. The first six already obsolete M2A1s were delivered in December 1940 and 88 more were delivered in 1941. Rock Island was incapable of producing sufficient numbers, and in August 1940, the Chrysler Motors Corporation was contracted for 1,000 M2A1s to be delivered by August 1942. The massive Detroit Tank Arsenal first had to be built by the US Army at Warren, Michigan, and would be operated by Chrysler.

Battle reports from Poland told of the German PzKfz IV with a short 75mm gun employed for infantry support and the PzKfz III with a high-velocity 37mm. Both tanks had low profiles. In a rush to field something comparable, work began in the United States on what was hoped to be a formidable tank, the M3 medium. The German offensive into the Low Countries and France, coupled with the expanded use of the PzKfz IV, reinforced the need for a heavily armed US medium tank. Additionally, in late 1940, PzKfz III’s began mounting a short 5cm gun. The Chrysler M2A1 contract was cancelled the same month it was let, and a new contract was granted for 1,000 M3s. The existing M2A1s were used as training tanks.