.280 British

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.280 British
Various .280 ball cartridges. The orange-cased cartridge is made out of aluminium.
Type	Rifle
Place of origin	United Kingdom
Service history
Used by	British
Production history
Designer	British Army
Designed	1945
Specifications
Case type	rimless, bottlenecked[1]
Bullet diameter	.284 in (7.2 mm)
Neck diameter	.313 in (8.0 mm)
Shoulder diameter	.448 in (11.4 mm)
Base diameter	.470 in (11.9 mm)
Rim diameter	.473 in (12.0 mm)
Rim thickness	.049 in (1.2 mm)
Case length	1.71 in (43 mm)
Overall length	2.54 in (65 mm)
Rifling twist	1:8.66 in (220 mm)
Maximum pressure	45,000 psi (310 MPa)
Ballistic performance
Bullet mass/type Velocity Energy 139 gr (9 g) Ball 2,270 ft/s (690 m/s) 1,595 ft⋅lbf (2,163 J) 140 gr (9 g) Ball 7 mm Mk 1Z 2,549 ft/s (777 m/s) 2,019 ft⋅lbf (2,737 J)
Source(s): Cartridges of the World [2]

The .280 British was an experimental rimless bottlenecked intermediate rifle cartridge. It was later designated 7 mm MK1Z, and has also been known as .280/30, .280 Enfield, 7 mm FN Short and 7×43mm.

Like most armed forces in the immediate post-World War II era, the British Army began experimenting with lighter rounds after meeting the German StG 44 in combat. The Army began development in the late 1940s, with subsequent help from Fabrique Nationale in Belgium and the Canadian Army. The .280 British was tested in a variety of rifles and machine guns including the EM-2, Lee–Enfield, FN FAL, Bren, M1 Garand and Taden gun.

Despite its success as an intermediate cartridge, the .280 British was not considered powerful enough by the US Army and several variants of the .280 British were created in an attempt to appease the US Army. However, the US Army continued to reject these variants, ultimately adopting the cartridge that was then designated the 7.62×51mm NATO.