Machine gun. The Gatling gun consists of ten barrels which revolve round a central axis. The centre fire cartridges are fed into the gun from a magazine mounted on top which holds 240 rounds. The barrels are rotated manually by a hand crank at the rear of the gun - turning the crank forward rotates the entire barrel and lock unit. Each barrel is fired as it reaches the lower right hand position. The calibre is 0.65in. The gun is mounted on a naval cone mounting. The Royal Navy adopted the Gatling gun in 1871 and it was used from the 1870s for coast defence work, by the Naval Brigades and mounted in the tops of ships. The Gatling was manufactured under license by W Armstrong & Co. It was used during the Zulu War of 1879 and the Egypt Campaigns of 1882-1889.