Ian Forrester: Thanks for your response, but here is my follow-up question re British guns originally chambered for 2 3/4 inch shells. Maybe the makers never asked that they be proofed as "magnums." Case in point, I bought from Christies last year a pigeon gun manufactured by an esteemed Italian maker in the mid 1960s. For some reason, there were no Italian or any other proof marks on the gun. Accordingly, Christies (or the owner more likely) had to have it proofed before they could sell it. The marks read 12/70 900 BAR, although I have no doubt that this gun can and has digested (and was made to digest)hot pigeon loads. So maybe when Purdey or whoever built a 2-3/4 inch chambered gun,they didn't bother to get it proofed for "magnum" (US) shells since it was not necessary to sell or export it; however, that does not necessarily mean that the gun would not or could not have been so proofed.
