The MiG-3's standard armament was one UBS machine gun and two ShKAS machine guns, all mounted in the engine cowling and synchronized to fire through the propeller arc. In contrast, most versions of the German Messerschmitt Bf 109 that it encountered had one cannon and two machine guns (although the Bf 109F used during Operation Barbarossa had the 15mm MG 151/15, meaning that it was armed little better than the MiG). To remedy this problem, 821 aircraft were built with one 12.7 mm UBK machine gun in a pod under each wing in mid-1941. This lowered its speed by about at all altitudes, which was unpopular with the pilots, some of whom removed the pods. One hundred aircraft were equipped with a pair of UBS machine guns in lieu of the ShKAS weapons. Another 215 aircraft also had just the UBS machine guns but were fitted to carry six RS-82 rockets. A total of 72 aircraft mounted a pair of 20 mm ShVAK cannon. A wide variety of armaments were experimented with by various units at the requests of their pilots or to make up shortages.