The .303 British (designated as the 303 British by the C.I.P. and SAAMI) or 7.7×56mmR, is a calibre rimmed rifle cartridge. The .303 inch bore diameter is measured between rifling lands as is the common practice in Europe which follows the traditional black powder convention. It was first manufactured in Britain as a stop-gap black powder round put into service in December 1888 for the Lee–Metford rifle. From 1891 the cartridge used smokeless powder which had been the intention from the outset, but the decision on which smokeless powder to adopt had been delayed. It was the standard British and Commonwealth military cartridge for rifles and machine guns from 1889 until it was replaced by the 7.62×51mm NATO. Cartridge specifications The .303 British has 3.64 ml (56 grains H2O) cartridge case capacity. The pronounced tapering exterior shape of the case was designed to promote reliable case feeding and extraction in bolt-action rifles and machine guns alike, under challenging conditions. .303 British maximum C.I.P. cartridge dimensions. All sizes in millimeters (mm). Americans would define the shoulder angle at alpha/2 ≈ 17 degrees. The common rifling twist rate for this cartridge is 10 in), 5 grooves, Ø lands = , Ø grooves = , land width = and the primer type is Berdan or Boxer (in large rifle size). According to official rulings of the C.I.P. (Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives), the .303 British can handle up to Pmax piezo pressure. In C.I.P. regulated countries every rifle cartridge combo has to be proofed at 125% of this maximum C.I.P. pressure to certify for sale to consumers. This means that .303 British chambered arms in C.I.P. regulated countries are currently (2014) proof tested at PE piezo pressure. The SAAMI (Sporting Arms and Ammunition Manufacturers' Institute) maximum average pressure (MAP) for this cartridge is piezo pressure (45,000 CUP). The measurement is the nominal size of the bore measured between the lands which follows the older black powder nomenclature. Measured between the grooves, the nominal size of the bore is . Bores for many .303 military surplus rifles are often found ranging from around up to . Recommended bullet diameter for standard .303 British cartridges is . Military use History and development During a service life of over 70 years with the British Commonwealth armed forces the .303-inch (7.7 mm) cartridge in its ball pattern progressed through ten marks which