The M2 Machine Gun or Browning .50 Caliber Machine Gun is a heavy machine gun designed towards the end of World War I by John Browning. The M2 has been referred to as “Ma Deuce”, as a GI phonetic slang or “the fifty” in reference to its caliber. It is effective against infantry, unarmored or lightly armored vehicles and boats, light fortifications and low-flying aircraft. The M2 machine gun has been in production longer than any other machine gun.