M2 Browning

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 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 infantry type is Browning Machine Gun, Cal. .50, M2, HB, Flexible. It has been used against infantry, light armored vehicles, watercraft, 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 M2HB (heavy barrel) is manufactured in the U.S. by General Dynamics, Ohio Ordnance Works, U.S. Ordnance, and FN Herstal for sale to the U.S. government and other nations via Foreign Military Sales.

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 pierce 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 0.50 inches (12.7 mm) and a muzzle velocity of at least 2,700 feet per second (820 m/s).

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 cartridge in an anti-tank rifle, but Pershing insisted the cartridge be rimless. The first .50-caliber machine gun underwent trials on 15 October 1918. It fired at less than 500 rounds per minute, and the muzzle velocity was only 2,300 ft/s (700 m/s). Cartridge improvements were promised. The gun was heavy, difficult to control, fired too slowly for the anti-personnel role, and was not powerful enough against armor.

While the .50-caliber was being developed, some 13.2×92mmSR Mauser 1918 T-Gewehr anti-tank rifles and their ammunition were captured. The 13.2 mm German rounds had a muzzle velocity of 2,700 ft/s (820 m/s), an 800 gr (52 g) bullet, and could penetrate armor 1 in (25 mm) thick at a range of 250 yd (230 m). Winchester improved the .50 caliber round to have similar performance. Ultimately, the muzzle velocity was 2,750 ft/s (840 m/s).

Efforts by Browning and Fred T. Moore resulted in the water-cooled, .50 caliber M1921 Browning machine gun and an aircraft version. These guns were used experimentally from 1921 until 1937. They had lightweight barrels and the ammunition fed only from the left side. Service trials raised doubts about whether the guns would be suitable for aircraft or for anti-aircraft use. A heavy barrel M1921 was considered for ground vehicles.

John M. Browning died in 1926. Between 1927 and 1932, S. H. Green studied the design problems of the M1921 and the needs of the armed services. The result was a single receiver design that could be turned into seven types of .50 caliber machine guns by using different jackets, barrels, and other components. The new receiver allowed right or left side feed. In 1933, Colt manufactured several prototype Browning machine guns (including what would be known as the M1921A1 and M1921E2). With support from the Navy, Colt started manufacturing the M2 in 1933. FN Herstal (Fabrique Nationale) has manufactured the M2 machine gun since the 1930s. General Dynamics, U.S. Ordnance and Ohio Ordnance Works Inc. are other current manufacturers.^{[citation needed]}