M1919 Browning

The M1919 Browning is a .30 calibre medium machine gun that served through most of the twentieth century as a light infantry, coaxial, vehicle, aircraft and anti-aircraft weapon for the United States and dozens of other countries. It is the air-cooled development of John M. Browning's water-cooled M1917, the standard American machine gun of the First World War: the water jacket was too heavy and too vulnerable for use in tanks, so Browning dropped it and fitted a heavier barrel instead. Some 439,000 were built between 1919 and 1945.

The gun is short-recoil operated and fires from a closed bolt, feeding from 250-round cloth or disintegrating metallic belts. Six variants of the basic design were produced. The M1919A1 strengthened the bottom plate for use in Mark VII tanks; the M1919A2 was a lightened cavalry model with an 18-inch barrel; and the M1919A3 was its infantry equivalent. The definitive M1919A4, with blueprints completed in late 1936, replaced the short barrel with a 24-inch heavy "bull barrel" and added a recoil booster, because the earlier short-barrelled guns did not generate enough recoil to cycle reliably. The front sight moved from the barrel jacket to the receiver for easier vehicle mounting, the jacket gained circular cooling holes in place of slots, and a recoil buffer was added to soften the bolt's impact on the backplate.

The M1919A6, first used in combat in autumn 1943, was a stop-gap attempt to match the German MG 34 and MG 42 as a portable squad automatic. It clamped a metal buttstock to the backplate, added a bipod and muzzle booster at the front and a carrying handle on the jacket, and used a lighter barrel that could at last be changed from the front rather than by field-stripping the entire gun. At 15 kg it remained considerably heavier than the MG 34 or MG 42 and was never satisfactory. A dedicated aircraft version, the .30 AN/M2, thinned the receiver walls and barrel to cut weight by a third and raised the cyclic rate to 1,200-1,500 rounds per minute; it was re-engineered with help from FN Herstal and was widely fitted to American aircraft early in the Second World War before rifle-calibre defensive guns became obsolete in air combat.

The M1919 saw service in the Second World War, Korea and Vietnam. The arrival of general-purpose machine guns in the 1950s, and of the M60 in US Army service, pushed it into secondary roles, but it did not disappear. The US Navy converted large numbers to 7.62x51mm NATO as the Mk 21 Mod 0 and mounted them on riverine craft in Vietnam. Many NATO countries made the same conversion and kept their guns into the 1990s. The Israel Defense Forces used tripod and vehicle-mounted M1919A4s converted to 7.62mm on armoured vehicles and M3 half-tracks from the 1960s to the 1990s, developing an improved belt link that worked with .30-06, 7.62mm NATO and 8x57mm ammunition alike. The gun remains in limited use in a number of countries today.