Authored By Dan Alex (Updated: 5/9/2016):
Famed American gunsmith John Moses Browning, having already developed a successful history in the design and production of small arms, took to designing a new machine gun. He undertook several key experiments between recoil-operated and gas-operated systems and came away with the belief that recoil-operated systems were the way to go, citing the latter's potential. In 1890, Browning received his US Patent for a recoil-operated machine gun and, despite the weapon's availability by 1910, the powers-that-be in the US Army found little interest in the Browning creation. This would all change with America's involvement in World War 1 by April of 1917. By then, the Browning M1917 was accepted into service after some impressive test firings for the US Army. In one such showing, the M1917 chewed through 20,000+ rounds of ammunition without a single malfunction.
Despite the need for a heavy machine gun system (and preferably of indigenous design for availability's sake), the US Army only received a fraction of the available M1917s by the time Doughboys of the American Expeditionary Force went to France. This meant that only the last few groups of American units were actually issued the M1917 for use in combat. As such, the US Army was forced to rely on the purchase of machine guns from her Allies, namely France. However, in the short time that the M1917 was in service in the conflict, it was noted for her strong qualities - mainly her reliability under fire and her high rate-of-fire.
Water-Cooling Over Air-Cooling
The M1917 made use of a water-filled cooling "jacket" fitted around the barrel. This jacket helped to dissipate the heat generated around the gun barrel as a result of each successive firing. In some ways, this method of cooling proved more efficient over other air-cooled types. However, water-cooling carried with it some inherent disadvantages. A fresh water supply would have to be made available for the crew to replenish the water container once the local supply was expended. This therefore required additional crewmembers for optimal support of the weapon. Couple that with the fact that the water-cooled jacket and water, along with the tripod, ammunition and gun itself, made for one cumbersome system, it was not uncommon to need up to four personnel to port and man the weapon.
In air-cooled machine guns the barrel was, of course, cooled by the air around it. While effective to an extent, it forced the operator to wield the weapon through short-controlled bursts of fire to allow for adequate cooling of the barrel in between trigger presses. Additionally, the barrel would eventually have to be changed to keep it from overheating outright and this often proved a time-consuming affair - not to mention the dangers in handling a red hot barrel under fire.
In either regard, however, each form of cooling held with it some advantages and disadvantages. It should be noted that water-cooled machine guns eventually gave way to air-cooled machine guns by the time of the modern age of warfare.
John Browning developed his recoil-operated system to take advantage of the recoil force found in the expanding powder gasses of each successive shot. The action pushed the barrel and bolt rearwards until stopped automatically to which the ammunition feed sprang into action and inserted a live round into the chamber from the available ammunition belt. By this time, the bolt was set into place by the recoil spring and the weapon was made ready to fire once more. If picture in a fast, repeated action, one gains a sense of the power provided for by the M1917. This operation afforded the M1917 its recoil-operation and allowed for full automatic fire at 400 rounds per minute in the base M1917 and (ultimately) upwards of 600 rounds per minute in the revised M1917.
External design of the Browning M1917 followed much in line with the German Maxim 08 and British Vickers before it (it should be noted that the Browning design has no relation to either weapon system). The main mechanical functions of the weapon were held in a rectangular body. Attached to the foreend of the body was the type's identifiable cylindrical water jacket used to cool the barrel with a portion of the barrel muzzle extending out some at the bottom edge of the jacket. A carrying handle could be attached along the top of the barrel jacket for some level of portability. The trigger was part of a spade grip assembly fitted to the rear of the body and proved an effective method of distinguishing the Browning design from both the German Maxim and British Vickers. A mounting leg was present at the forward underside base of the weapon for fitting onto its tripod. The tripod was a heavy, tubular affair that provided the operator with both a swivel and elevation action to train effectively onto targets. A flip-up type sight was situated at the forward end of the upper body. Ammunition feed was situated along the left side of the body and utilized a fabric 250-round belt held in an ammunition box. This ammunition box contained M1906 .30-06 cartridges and pictures show that the box could be fitted directly alongside the weapon body or kept along the ground when firing. The operator maintained a sitting or prone position behind the weapon while test-firing photographs also showed a hunched-over operator stance being taken.