Quote Originally Posted by Peter Laidlericon View Post
In Army rifles the high quality HXP brass did tend to expand into and hold on to any small imperfections in the chamber. Could this be what's happening?
That seems pretty reasonable. I have not fired surplus ammo in this No1MkIII* but in a friends rifle the surplus stuff extracted much easier however firing it was a bit dicey as the number of hang-fires was pretty high. If I recall that batch was from 1954 or so. I'll have to try some of the surplus stuff in my rifle.