8x71

From Epiverse

The 8x71mm cartridge was created during the Third War by BSA on contract from the British Army to produce a heavy cartridge - primarily to more effectively counter the well-armoured New World infantry. It has good ballistic performance for such a large round, lending itself to marksman applications. An example of this is the BSA Lee, usually used by the British Army for issue to snipers and designated marksmen.