Hi Justin,thanks for the imput,I've also got the same rnd. Trouble is its 1.2830in the Brit rnd is 1.2600, not sure why. I'll put some photos up soon. I don't think US rnds were used as separates in Brit munitions factories we supplied our own components to our own factories as far as I know. The rnd and case were made at GCF3 Blackpole Worcestershire. I've just had the rnd under a scope and it's possiblely got a P on it I'm not sure. Think this is one for litriture boys, if they used contract projectiles in home cases then that's my answer if not then I'm stumped. Regards Pete.