Safety Question

[Alan de Enfield]

I wonder, how and under what circumstances would the Birmingham Proof House proof a DP rifle? Wouldn't they have known the meaning of DP and rejected it at once?

The proof house does not pre-judge any firearm. They are asked to test it and they do.
They do not check for headspace, they just fire a 'proof load' and if it doesnt explode/fall apart or bulge the barrel it passes.

I guess that if they had one of the DP's with a hughe great hole thru' the action/barrel that they may notice it