as a self-propelled howitzer or a tank, one exception being Sweden, which continued to develop casemate assault guns post war, such as the ikv 72, all the way into the 1960s before settling on a turreted design in 1968, becoming the ikv 91. The Soviet Union continued funding development of new assault guns as late as 1967, although few of its postwar designs were adopted in large numbers. In Soviet and other Eastern European armies, the traditional assault gun was primarily superseded by tank destroyers such as the SU-100 capable of supporting either infantry or armor. Since the 1980s however the multi-purpose assault gun concept has seen a resurgence, mainly in the form of turreted wheeled designs, such as the South African Rooikat and Italian Centauro. History World War II Assault guns were primarily developed during World War II by the forces of Nazi Germany and the Soviet Union. Early in the war, the Germans began to create makeshift assault guns by mounting their infantry support weapons on the bed of a truck or on obsolete tanks with the turret removed. Later in the war, both the Germans and the Soviets introduced fully armoured purpose-built assault guns into their arsenals. Early on, the Soviets built the KV-2, a variant of the KV-1 heavy tank with a short-barreled 152 mm howitzer mounted in an oversized turret. This was not a success in battle, and was replaced with a very successful series of turretless assault guns: the SU-76, SU-122, and the heavy SU-152, which were followed by the ISU-122 and ISU-152 on the new IS heavy tank chassis. The primary German assault gun was the Sturmgeschütz III (StuG III). At about the same time (March 1942) as the howitzer-like KwK 37 gun was dropped from the Panzer IV's use, its Sturmkanone equivalent in the StuG III up to that time, was likewise replaced with a longer-barreled, high-velocity dual-purpose 75mm gun that had also been derived from the successful PaK 40 anti-tank towed artillery piece. The Germans also built a number of other fully armoured turretless assault guns, including the StuG IV, StuIG 33B, Brummbär and Sturmtiger. The latter two were very heavy vehicles, and were built only in small quantities. Battalions of assault guns, usually StuG IIIs, commonly replaced the intended panzer battalion in the German panzergrenadier divisions due to the chronic shortage of tanks, and were sometimes used as makeshifts even