First prototypes of German tank destroyer Sturmgeschutz III (StuG III) were built in 1937 and based on PzKpfw III Ausf. B tank. Vehicles were armed with short-barelled 75mm gun. From spring, 1942, StuG IIIs were equipped with StuK 40 75mm gun. Self propelled guns StuG III served in separated assault artillery units, and later in self propelled guns brigades. They were also used in support units of armoured divisions.