Irish Contract No4 mk2

[Beerhunter]

BV, BP and BM are pre-1954 Proof marks applied by the Birmingham Proof House. In each case the "B" refers to Birmingham, (as opposed to London). They were replaced post-1954 by BNP (for Nitro Proofed guns).

I think that I may have explained the British Proof system before ans so a search should find it.