The Russian Front battles during 1941 soon revealed that the Soviet light tanks such as the T-60 and newer T-70 (many thousands of which had been produced prior to the German invasion) were virtually useless on the battlefield. It was therefore decided to combine the chassis of the T-70, already in production, with the excellent ZIS-3 and ZIS-76 guns to create a mobile anti-tank weapon to increase the firepower of the Soviet armoured formations.
The first SU-76s (The initials stand for Samokhodnaya Ustanovka – self propelled [gun] mounting) appeared in late 1942 and by mid 1943 they were being deployed in appreciable numbers. In order to accommodate the longer hull needed as a self-propelled mounting an additional road wheel was incorporated on each side, and Independent torsion bars for each road wheel were used for the suspension. The SU-76 was initially powered by a pair of 70bhp GAZ -202 6-Cylinder inline water- cooled petrol engines, but these proved unreliable in combat and later production models employed 85bhp GAZ-203 engines.
The gun utilised was the 76.2mm model 1942, 41.5 calibres long, with sixty (mostly anti-tank) rounds carried for it. This was mounted in an armoured box on the rear of the hull and had a limited traverse of 32 degrees.
Mass production began in early 1943 at the 37th and 38th factories of the GAZ Automobile Works at Gorki, and by 1945 over 12,500 SU-76s had been built. As a Wartime expedient, there were few comforts for the four-man crew, who somewhat cruelly nicknamed the vehicle as 'The Bitch'. SU-76 regiments in service would normally comprise a small Headquarters section and three companies of 4-5 SPGs each.
The lightly armoured open topped fighting compartment was unfortunately a serious weakness in battle that severely restricted tank hunting operations, and by the end of 1943 the SU-76's gun had already become seriously outranged by more powerful German weapons like those carried by the new Tiger and Panther tanks. As the better SU-85 became available from early 1944 to fill the self-propelled anti-tank role, the SU-76s were turned over to the infantry support role (a proposal to fit a larger gun not being pursued), and by 1945 many SU-76s were retrospectively converted into ammunition carriers or recovery vehicles.
After World War II, many SU-76s were supplied to China and North Korea, numbers seeing service with the Communist forces during the Korean War.
Sources:
Armoured Fighting Vehicles (Philip Trewbitt, Dempsey-Parr, 1999)
Tanks and other Armoured Fighting Vehicles 1942-45 (B.T. White, Blandford Press, 1975)
The Illustrated Encyclopaedia of Military Vehicles (Ian V Hogg & John Weeks, Hamlyn, 1980)