The M4A1 Sherman first saw combat at the Second Battle of El Alamein in October 1942 with the British 8th Army. The first U.S. Shermans in battle were M4A1s in Operation "Torch" the next month. At this time, Shermans successfully engaged German Panzer IIIs with long barreled 50mm L60 guns, and Panzer IVs with short barreled 75 mm L24 guns. Additional M4 and M4A1s replaced M3 Lees in U.S. tank battalions over the course of the North African campaigns. However, by June 1944, most German tanks were up-gunned and 75 mm Shermans were outgunned. The M4 and M4A1 were the main types in U.S. units until late 1944, when the Army began replacing them with the preferred M4A3 with its more powerful engine. Some M4s and M4A1s continued in U.S. service for the rest of the war.