M1917 Browning machine gun

Browning Model 1917
Browning Model 1917A1 water-cooled machine gun
Type	Heavy machine gun
Place of origin	United States
Service history
In service	1917 – late 1960s (U.S.)
Used by	See Users
Wars	World War I World War II Korean War Vietnam War Battle of Vimy Ridge
Production history
Designer	John M. Browning
Designed	1917
No. built	128,369
Variants	M1917, M1917A1
Specifications
Weight	103 lb (47 kg) (gun, tripod, water, and ammunition)
Length	980 mm
Barrel length	24 in (609 mm)
Cartridge	.30-06 Springfield
Action	Recoil-operated automatic
Rate of fire	450 round/min, 600 round/min for M1917A1
Muzzle velocity	2,800 ft/s (853.6 m/s)
Feed system	250 round fabric belt

The M1917 Browning machine gun is a heavy machine gun used by the United States armed forces in World War I, World War II, Korea, and to a limited extent in Vietnam; it has also been used by other nations. It was a crew served, belt-fed, water-cooled machine gun that served alongside the much lighter air-cooled Browning M1919. It was used at the battalion level, and often mounted on vehicles (such as a jeep). There were two main iterations of it: the M1917, which was used in World War I; and the M1917A1; which was used thereafter. The M1917, which was used on some aircraft as well as in a ground role, had a cyclic rate of 450 rounds per minute; the M1917A1 had a cyclic rate of 450 to 600 rounds per minute.

In 1900, John Moses Browning filed a patent for a recoil-powered automatic gun. Browning did not work on the gun again until 1910, when he built a water-cooled prototype of the 1900 design. Although the gun worked well, Browning improved the design slightly. Browning replaced side ejection with bottom ejection, added a buffer for smoother operation, replaced the hammer with a two piece firing pin, and some other minor improvements. The basic design of the gun was still the 1900 design.

The Browning is a water-cooled heavy machine gun, though some experimental versions were made that did not use a water jacket; the air-cooled M1919 was later developed as a medium machine gun. Unlike many other early machine guns, the M1917 had nothing to do with Maxim's toggle lock design. At 47 pounds (21 kg), it was much lighter than contemporary Maxim type guns such as the first 137-pound (62 kg) German Maschinengewehr 08 (08/15 model: 43 lb (20 kg)) and the British Vickers machine gun, while still being highly reliable. The only similarities with the Maxim or Vickers are the principle of recoil operation, T-slot breechblock, "pull-out" belt feed, water cooling, and forward ejection. Its sliding-block locking mechanism saved weight and complexity, and was used in many previous Browning designs. The belt fed left-to-right, and the cartridges were stacked closer together than Maxim/Vickers (patterns copied by most guns later).