 Even by 1944, most M4 Shermans kept their dual-purpose 75 mm gun.By then, the M4 was inferior in firepower and armor to increasing numbers of German heavy tanks, but was able to fight on with the help of considerable numerical superiority, greater mechanical reliability, better logistical support, and support from growing numbers of fighter-bombers and artillery pieces.Some Shermans were produced with a more capable gun, the 76 mm gun M1, or refitted with a 76.2mm calibre Ordnance QF 17-pounder gun by the British (the Sherman Firefly).