M10 Tank Destroyer - Development

Development

US combined-arms doctrine on the eve of World War II held that tanks should be designed to fulfill the infantry support and exploitation roles. The anti-tank warfare mission was assigned to a new branch, the tank destroyer force. Tank destroyer units were meant to counter German blitzkrieg tactics. Tank destroyer units were to be held as a reserve at the Corps or Army level, and were to move quickly to the site of any enemy tank breakthrough, maneuvering aggressively to destroy enemy tanks. This led to a requirement for very fast, well-armed vehicles. Though equipped with turrets (unlike most tank destroyers of the day), the typical American design was more heavily gunned, but more lightly armored, and thus more manoeuvrable, than a contemporary tank. The idea was to use speed and agility as a defense, rather than thick armor, to bring a powerful self-propelled gun into action against enemy tanks.

The 3-inch Gun Motor Carriage T35 was the prototype of the M10. It was equipped with a 3-inch (76.2 mm) gun in a new sloped, circular, open-topped turret, developed from the Heavy Tank T1/M6 turret, and mounted on an early-production Medium Tank M4A1 hull.

This prototype was further developed by sloping the hull, using an M4A2 chassis, and replacing the circular turret with a pentagonal version; this model was designated 3-inch Gun Motor Carriage T35E1. In June 1942 the T35E1 was finalized as the 3-inch Gun Motor Carriage M10 and ordered into full production. Towards the end of production the 76 mm gun M1 was installed in the last 300 or so M10's, as it was being fitted into the new production M4 Sherman tank at the time. The 76 mm M1 offered slightly better anti-armour performance than the previous 3" gun M7.

A British variant, designated "17pdr SP Achilles", was developed by mounting the successful 17-pounder anti-tank gun in a modified turret. The 17-pounder was of a similar bore, but had far superior armor penetration capability. It was used by the British, Canadian and Polish armies in Italy and North-West Europe.

After World War II, a batch was acquired by the Republic of China Army as demilitarized surplus items. The vehicles' main guns were rendered useless prior to delivery and consequently replaced in 1949 with ex-Imperial Japanese Army 150mm infantry howitzers.