Definitions for ".303 British"
British is a rifle and machine gun cartridge first developed in Britain in the 1880s as a blackpowder round, later adapted to use cordite and then smokeless powder propellant. It was the standard British and Commonwealth cartridge from 1889 until the 1950s, when it was replaced by the 7.62 x 51 mm NATO round, and in the 1980s by the 5.56 x 45 mm NATO (.223 inches) in most roles. It is a rimmed cartridge and is therefore not entirely suitable for use in modern automatic weapons, but remains popular due to the large number of surplus military rifles chambered for the round which have been released to the civilian market, some of which have subsequently been modified for sporting use.