Vickers machine gun in action at the Somme
The Vickers was a water-cooled weapon. A jacket around the main barrel - seen above - held about one gallon of water and to keep water loss to a minimum, a rubber hose was attached to a container that condensed steam. The machine gun used the same ammunition as the Lee Enfield rifle (0.303 inch bullets) and could fire at a rate of 450 bullets a minute. Such a rate of fire could cause havoc for an attacking force - though bullet wastage was high as many bullets failed to hit a target. However, this would have been true with any machine gun in World War One.
The Vickers weighed about 20 kg and invariably had to be used with a tripod. Therefore, it was not the easiest weapon to transport around a battlefield. A Vickers gun team could be as many as six men. However, used in a defensive and static position, it proved to be a deadly weapon of war accounting for many German casualties.
The failings of the Vickers as stated above, led to it being phased out on the Western Front by the end of 1915. It was replaced by the Lewis gun, though it was used in other campaigns involving British forces.
However, the Vickers, despite the difficulty in transporting it, retained its reputation as a hard-hitting and reliable weapon. In an attack it was awkward to move and set-up - but in defence it was a very dangerous weapon for anyone attacking a position defended by Vickers machine guns.