45 mm anti-tank gun M1937

The 45 mm anti-tank gun model 1937, nicknamed the Sorokapyatka, was a light quick-firing anti-tank gun used in the first stage of the German-Soviet War. It was created by Soviet artillery designer M.N. Loginov of Plant No. 8 after the arrest and execution of former designer V. von Behring. Due to insufficient armor penetration it was replaced in service by the longer-barreled M-42 in 1942. Production of the gun ceased in 1943 with a total of 37,354 units built from 1937 to 1943.

Source: Wikipedia