Authored By Dan Alex (Updated: 7/27/2016):
The original Maxim machine gun was developed by American Hiram Maxim of Maine who became a British citizen in 1900. The weapon relied on one of the first uses of recoil operation known with patents appearing as far back as 1883. Maxims served well into the 1950s despite their late-1880s origins even seeing action in the Korean War (1950-1953).
The British Army adopted the new Vickers design in 1912 (as the "Gun, Machine, Vickers, .303in Mark 1") and it became its standard support machine gun thereafter. The weapon was initially categorized as a "heavy machine gun" though this designation later gave way to a medium classification upon the arrival of other truly heavy weapons. In the field, the design structure proved robust and the action was highly reliable. Key detriments lay in jamming at the feed and the generally slow rate-of-fire for a weapon of this class. As the Vickers Machine Gun was a complete weapons "system", the design was much more than the gun itself. The entire Vickers Machine Gun system consisted of the machine gun proper, the water condensing can containing the required water supply for cooling, the condensing hose running from the can to the barrel jacket, an optional integrated collimating sight at the rear of the receiver, a wooden ammunition box containing 250 rounds of .303 British cartridges served from fabric belts and the gun mount (Maxim-type sledge or - later - a collapsing tripod). A canvas jacket could be wrapped around the barrel jacket to reduce rising heat from blurring vision ahead of the sight. A muzzle booster could be fitted at the barrel business end for an improved rate-of-fire, providing additional recoil force to the firing action. The operator managed the firing action and traverse through a pair of spade grips fitted at the rear of the receiver. The hinged cocking handle was set to the right side of the body in a conventional fashion.
Of note here is the water-cooled nature of machine guns like the Vickers. These weapons relied on a steady water supply pumped into a barrel jacket that surrounded the barrel assembly. During firing, this action served to cool a hot barrel and prevent it from overheating and fracturing or deforming. The condenser can used in water-cooled machine guns - while supplying the barrel jacket with water - also served to condense some of the steam being generated by the heat of the barrel. If this were not so, the position of the machine gun and crew would be quickly given away to the enemy with the rising steam being the primary indicator. For the Vickers series, the water surrounding the barrel in the jacket would start to evaporate after roughly 750 rounds had been fired. A fresh water supply was as necessary as was an ammunition supply.
The Vickers fired the .303 British cartridge from a 250-round canvas belt. The cartridge was developed in 1888 and first adopted in the Lee-Metford service rifle series before becoming the standard British and Commonwealth cartridge around the world. The cartridge itself was a rimmed design with a noticeable bottleneck and a proven manstopper. The Vickers machine gun action itself revolved around a recoil operation with gas boosting capable of a sustained rate-of-fire of 450 to 500 rounds per minute. Muzzle velocity was rated at 2,450 feet per second with an effective range out to 2,190 yards - maximum ranges out to 4,500 yards though with less accuracy. Sighting was primarily through iron mountings but a collimating sight could be used for long-range service (introduced in 1943). The weapon weighed between 33lbs and 50lbs which required multiple crew for its operation and transport.