.303 British

.303 British
Left to right: .303 British, 6.5×50mmSR Arisaka and .30-06 Springfield ballistic tip ammunition
Type	Rifle
Place of origin	United Kingdom
Service history
In service	1889–present
Used by	United Kingdom and many other countries
Wars	Second Boer War Boxer Rebellion World War I Various Colonial conflicts Irish War of Independence Irish Civil War World War II Indonesian National Revolution Indo-Pakistani Wars Greek Civil War Malayan Emergency French Indochina War Korean War Arab–Israeli War Suez Crisis Mau Mau Uprising Portuguese Colonial War Sino-Indian War Vietnam War Bangladesh Liberation War Soviet invasion of Afghanistan Nepalese Civil War Afghanistan conflict
Production history
Produced	1889–present
Specifications
Case type	Rimmed, tapered, bottleneck
Bullet diameter	7.92 mm (0.312 in)
Land diameter	7.70 mm (0.303 in)
Neck diameter	8.64 mm (0.340 in)
Shoulder diameter	10.19 mm (0.401 in)
Base diameter	11.68 mm (0.460 in)
Rim diameter	13.72 mm (0.540 in)
Rim thickness	1.63 mm (0.064 in)
Case length	56.44 mm (2.222 in)
Overall length	78.11 mm (3.075 in)
Case capacity	3.64 cm3 (56.2 gr H2O)
Rifling twist	254 mm (1-10 in)
Primer type	Large rifle
Maximum pressure (C.I.P.)	365.00 MPa (52,939 psi)
Maximum pressure (SAAMI)	337.84 MPa (49,000 psi)
Maximum CUP	45,000 CUP
Ballistic performance
Bullet mass/type Velocity Energy 150 gr (10 g) SP 844 m/s (2,770 ft/s) 3,463 J (2,554 ft⋅lbf) 174 gr (11 g) HPBT 761 m/s (2,500 ft/s) 3,265 J (2,408 ft⋅lbf) 180 gr (12 g) SP 783 m/s (2,570 ft/s) 3,574 J (2,636 ft⋅lbf)
Test barrel length: 24 in (610 mm) Source(s): Accurate Powder[1][failed verification]

The .303 British (designated as the 303 British by the C.I.P.^[2] and SAAMI^[3]) or 7.7×56mmR, is a .303-inch (7.7 mm) calibre rimmed tapered 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.^[4] 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^[2] in the 1950s.