Testing a barrel to see if it's safe to shoot?

[Ridolpho]

To get back to the OP- what is the best way to test a Nepali P53 type rifle to prove safety? With a British ordnance issue (or, I suppose a volunteer/commercial equivalent) P53 one knows it was subjected to, and survived, a pair of proof loads. Given that, to my knowledge, iron doesn't "age" in the short time and conditions we're talking about, assuming no intensive corrosion of visible defects, that proof still means something. Based on the little available material on the Nepali "P53's", I don't think it is known that they were even proofed. They may have been forged differently (twist) out of lower quality iron. Does one 70 grain load fired with a string constitute an adequate safety test? Can a "BP smithy" guarantee safety by examination? I would suggest looking for a real P53 made in England/Belgium/USA,etc?, or, possibly, a modern replica, if shooting is in your plans and you don't feel comfortable with your own knowledge of these issues.

edit: add photo. This is a worn out Snider I chopped up. This cut is just above the chamber in this converted 1859 P53. The thickness of the barrel is slightly greater than 0.20" (in the grooves) at this spot. That's a lot of good British iron! No wonder the original proof loads didn't blow up too many.

Ridolpho