a variant (different style) of the 7.92x57mm, the 7.92x33 mm "8mm kurz", was created as an intermediate cartridge intended to be used in urban warfare, as the german army learned from fighting in cities, mainly in russia after operation barbarossa. the 8mm kurz was used in the stg44 assault rifle. this round, weapon, and concept was picked up and expanded on by the russians after the war, and this led up to the development of the 7.62x39mm cartridge used in the sks45, ak47 (and variants), and the rpd light machine gun.