 The M1A1C gun, which entered production lines in March 1944, was threaded for a muzzle brake, but as the brakes were still in development, the threads were protected with a cap.The addition of a muzzle brake on the new M1A2 gun (which also incorporated a faster rifling twist leading to a slight accuracy increase at longer ranges) beginning in October 1944 finally solved this problem by directing the blast sideways.Army doctrine at the time emphasized the multirole ability of the tank, and the capability of the high explosive shell was considered important.