Pz.Kpfw.3 Ausf.D

Initially, the Panzer III had the same 3.7 cm gun as the infantry used in an anti-tank role, but later models were given the 5 cm KwK 38 gun. This was the largest gun that could be fitted within the physical limitations of the turret ring, but it turned out to be ineffective against Soviet T-34 and KV-1 tanks. The Panzer IV, which had a larger turret ring, was redesigned to mount the long-barrelled 7.5 cm KwK 40 gun and became the main German tank instead. Produced from 1942 onwards, the last version of the Panzer III (Panzer III N) mounted the short barrelled 7.5 cm KwK 37 L/24 which was used on the first Panzer IVs, meaning the Panzer III and the Panzer IV had effectively swapped roles. Production of the Panzer III ceased in 1943, but the StuG III assault gun, which was based on the Panzer III chassis, remained in production until the end of the war. About 18,000 vehicles based on the Panzer III chassis were produced between all variants --- by far the most of any German AFV design in World War II, and accounting for over a quarter of all tanks and assault guns produced by Nazi Germany.