Quote Originally Posted by Alan de Enfield View Post
Its the cartridge overall length (COAL) but is normally 2.22"

Wrong punch used ???????
I don't think its actually a UKicon proof mark, but some other country's (South Africa?) version of a CIP mark. I have a feeling that its related to the CIP measurement of the cartridge pressure (ie not chamber dimension) which, IIRC, is specified at a point on (for rimless) or near the case shoulder.

Then again I might be completely wrong!