The British adopted the 7.62x51mm round in the late 1950s along with the SLR. The British had developed a truly intermediate cartridge to go with its EM2 battle rifle in the 1960s in .280 calibre, however pressure from the US to standardise on a heavier round, closer to the .30 cartridge it already had in service resulted in NATO adopting the 7.62 round instead. The British introduced the L2A1 ball round in 1954 which was Berdan primed and had 44 grains of NRN nitrocellulose as its propellant. The case was a rimless design, with a boat tailed bullet made of gilding metal over an antimony core:

This particular round is the L2A2 which was introduced in 1955 with some strengthening to the casing based on experience in the field. The round was to be produced for many years, the headstamp on this round indicating it was made by Radway Green in 1993:

The powder was changed to ICI Nitrocellulose, however the bullet remained the same and weighed 144 grains:

The weight of the bullet and the powder within allowed it to have a velocity of 2700 fps.

This round has proved to be extraordinarily long lived and although no longer used in infantry rifles, it remains in service with the popular GPMG or ‘Gimpy’