Tank Destroyer Battalion (United States) - Vehicles

Vehicles

Some early units were equipped with towed 37 mm guns, but this was abandoned as soon as possible. In addition to the 75 mm-equipped M3 GMC, the original attempt to produce a tank destroyer, a vehicle was developed utilizing the common 37mm anti-tank gun. This was designated the M6 GMC, and was simply a 3/4 ton truck with a 37 mm gun mounted in the rear compartment. A large number were produced, equipping one platoon in each company, but this was abandoned after November 1942 and the vehicles exchanged for M3s. The M6 saw only limited service in North Africa, and was declared obsolescent in 1943. A few were used by Free French forces in Europe in 1944–45, and the 37mm gun mounts were added to a few M2 halftracks at the unit level.

The deficiencies of the M3 were quickly noted in the 1941 maneuver, and the experience gained allowed a "perfect" advanced tank destroyer to be planned, one which would give a high priority to speed. However, it would take some time to be developed, and a simpler design was looked for as a stopgap. It was decided to take the proven M4 Sherman chassis and give it a modified 3 inch high-velocity anti-aircraft gun; the resulting combination was designated the M10 Gun Motor Carriage (GMC). Compromises were made to the vehicle; the turret was left open and lightly armored, keeping the weight low in order to prioritize the speed of the vehicle. A small number were used in North Africa, and it became a standard vehicle thereafter.

The experience of employing the M3, M6 and M10 in North Africa all fed into the plans for the next generation tank destroyer, which eventually saw service as the M18 GMC, nicknamed the "Hellcat". It was equipped with a newly designed 76 mm gun—firing the same shell (from a different cartridge case) as that on the M10—mounted on an all-new chassis. This new design allowed it to be ten tonnes lighter than the M10, which allowed for a remarkable road speed of over 50 mph. However, it was still lightly armored—indeed, it had only half the armor of the M10—and suffered many of the survivability problems of its predecessors. The M18 began to see service in mid-1944.

The final tank destroyer to enter service was the M36 GMC. This was a development of the M10 hull with a large turret mounting a 90 mm high-velocity gun, the most powerful vehicle weapon which would be carried by American forces in Europe. A prototype was originally constructed in 1942, as an experiment, and the design was standardised in June 1944. In July, the European command requested that all M10 battalions be converted to M36s, and the first vehicles reached the front lines in September. It proved more than capable of countering heavy tanks – it was recorded as disabling a Panther tank at 3,200 yards – and its roots in the M10 meant that it possessed greater survivability than the M18. A modification of the M-18 upgunned to 90mm was never approved for series production.