The M2 machine gun or Browning .50 caliber machine gun (informally, "Ma Deuce") is a heavy machine gun that was designed near the end of World War I by John Browning. While similar to Browning's earlier M1919 Browning machine gun, which was chambered for the .30-06 cartridge, the M2 uses Browning's larger and more powerful .50 BMG (12.7 mm) cartridge. The design has had many designations; the official U.S. military 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. The gun has been used extensively as a vehicle weapon and for aircraft armament by the United States since the 1930s. It was heavily used during World War II, the Korean War, the Vietnam War, the Falklands War, the Soviet–Afghan War, the Gulf War, the Iraq War, and the War in Afghanistan. It is the primary heavy machine gun of NATO countries and has been used by many other countries as well. U.S. forces have used the M2 longer than any other firearm except the .45 ACP M1911 pistol, which was also designed by John Browning. The current M2HB (heavy barrel) is manufactured in the U.S. by General Dynamics Ohio Ordnance Works, and U.S. Ordnance for sale to the U.S. government and to allies via Foreign Military Sales. Foreign manufacturers such as FN Herstal produce it under licence. History Machine guns were heavily used in World War I, and weapons of larger than rifle caliber began appearing on both sides of the conflict. The larger rounds were needed to defeat the armor that was being introduced to the battlefield, both on the ground and in the air. Germany introduced the Junkers J.I aircraft, whose armor could render ineffective aircraft machine guns that used conventional rifle ammunition such as the .30-06. Consequently, the American Expeditionary Force's commander General John J. Pershing asked for a larger-caliber machine gun. Pershing asked the Army Ordnance Department to develop a machine gun with a caliber of at least and a muzzle velocity of at least . Around July 1917, John Browning started redesigning his .30-06 M1917 machine gun for a larger and more powerful round. Winchester worked on the cartridge, which was a scaled-up version of the .30-06. Winchester initially added a rim to the cartridge because the company wanted to use the