303 British

This became the official British military cartridge in 1888 and remained in that post until Great Britain adopted the official NATO chambering in the 1950s (the 7.62x51mm or 308 Winchester). As commonly happens with military chamberings, the 303 became extremely popular throughout its (extended) homeland, the entire British Empire. The original loading combined a 215-grain round-nosed bullet with a compressed charge of blackpowder. This was soon replaced with a cordite loading that generated more velocity but less chamber pressure. Performance of this long, heavy bullet, launched at moderate muzzle velocity was predictably good. It excelled when properly used against larger species of deer and antelope. Later, a more modern loading using a lighter, pointed bullet was standardized for the military. This case was the basis of an entire line of wildcats designed for bolt-action rifles that would properly handle such a case and particularly for various single-shot actions. Many of these wildcat numbers gained wide popularity, worldwide, but particularly in Australia and Canada. Ballistics of proper loads for use in any gun that is in good condition are sufficiently similar to the 308 Winchester so that the 303 is suitable for
precisely the same applications.