I chassis as a heavy assault gun. It still had six howitzers and an assault gun. An assault gun variant was also proposed. In the end the B42 came to power the Infanterikanonvagn 103 assault gun. The Saint-Chamond proved at last quite effective in this specialist assault gun role. It served in the Korean War, mostly as an assault gun. In compensation, it was reinforced by two tank destroyer battalions and an assault gun brigade. The same M-20 engine was later used on the ASU-57 light assault gun. In general, Red Army commanders viewed the ISU-122 as a good assault gun. Three US tanks and an assault gun escorted supply convoys to the forward positions. Each airborne division had one assault gun battalion with 31 ASU-85. American tank destroyer units were often used in the assault gun role for infantry support. The BT-42 was a Finnish assault gun, constructed during the Continuation War. One such example is the SU-76i assault gun based on captured Panzer III. Designated "SU-D15", the medium assault gun was intended as a replacement for the SU-122.