It was a crew-served, belt-fed, water-cooled machine gun that served alongside the much lighter air-cooled Browning M1919.

The only similarities with the Maxim or Vickers are the principles of recoil operation, T-slot breechblock, "pull-out" belt feed, water cooling, and forward ejection.

The belt fed left-to-right, and the cartridges were stacked closer together than Maxim/Vickers (patterns copied by most guns later).

The Army Ordnance Department showed little interest in machine guns until war was declared in April 1917.

[4]: 176  In the first test, the weapon fired 20,000 rounds with only a few malfunctions mostly related to poorly loaded cloth belts.

The Ordnance Board was impressed, but was unconvinced that the same level of performance could be achieved in a production model.

[4]: 176–177 The Army adopted the weapon as its principal heavy machine gun, utilizing the M1906 .30-06 cartridge with a 150-grain, flat-base bullet.

Production was complex as the several manufacturers producing the guns needed to establish assembly lines and create tooling.

[7] The Model 1917A1 was again used in the Second World War, and was primarily used with the M2 ball, tracer, and armor-piercing ammunition introduced just prior to the outbreak of hostilities.

Some were supplied to the UK for use by the Home Guard since all production of the .303 Vickers were needed to resupply the equipment abandoned during the Fall of France.

The M1917's weight and bulk meant that it was generally employed as a fixed defense or as a battalion or regimental support weapon.

In this latter role, the disassembled weapon was carried by machine gun squads advancing on foot, which could rapidly deploy it to support the infantry in offensive operations.

[10] The Model 1917 was slowly phased out of military service in the late-1960s in favor of the much lighter M60 machine gun chambered in the new 7.62 mm NATO cartridge.

[12] The last ones in regular US service were on the machine gun infiltration course at Fort Benning, Georgia, where their sustained-fire capability was an advantage in long nights of shooting over the heads of low-crawling trainees.

Some are still in use today by irregular military forces because the water cooled barrel allows for long periods of sustained fire.

An early fix was to attach a roughly horseshoe-shaped steel bracket around the rearmost part of the receiver.

The top covers also had a stronger feed pawl pivot arm installed, so the gun could handle the stress of pulling an ammunition belt from the ground.

From 1930, Belgian Fabrique Nationale produced air-cooled and water-cooled versions of the M1917, chambered in various calibers for domestic and export use.

[1]: 65–66 Kulspruta m/14-29 was the Swedish designation for the licensed M1917A1, produced by Carl Gustafs Gevärsfaktori in Eskilstuna, for infantry support.

[15] The 6.5mm bullet was found to be too light for long-range fire support and anti-aircraft use, so in 1932 the heavier 8×63mm patron m/32 cartridge was developed.

[15] These double cradles were also used as standard defense, mounted on a ring on the cab roof, on terrain vehicles and armored troop carriers like Terrängbil m/42 KP.

[18] The modifications included new iron sights (V-notch rather than loophole), lengthened butt handle, lengthened barrel, simplified rifle lock for easier exchange of used-up barrels and better handling, mounting adapted for both anti-personnel and AA fire and sights and grips adapted to suit both purposes.