The M2 Machine Gun, or Browning .50 Caliber Machine Gun is a heavy machine gun esigned towards the end of World War I by John Browning. It was nicknamed Ma Deuce by US troops or simply called "fifty-cal." in reference to its caliber. The design has had many specific designations; the official designation for the current infantry type is Browning Machine Gun, Cal. .50, M2, HB, Flexible. It is effective against infantry, unarmored or lightly-armored vehicles and boats, light fortifications, and low-flying aircraft.