Originally Posted by
Turnup
Not my gun and like you I want nothing to do with the whole idea - trying to keep my friend in one piece.
That is no answer to the question "What makes it illegal to submit a BP proofed gun for nitro proofing" You have asserted that to do so is illegal and when asked for support you in effect have simply repeated "It is against the law (CIP and Proof Acts). There is no such provision in either of them. Neither is there any particular law against owning or shooting a gun which is not proofed, or is out of proof or in loading it with more than the proofed load. The law prohibits only the sale of such an item.