4seventy,
Yes, I would put some money on it that no-one can prove such a thing has happened to a nitro proofed rifle, say a couple of hundred bucks....It would be worth it to me to put this question to rest after chasing it for 20 years...

The more I have talked to the real experts in this field, the more I am convienced that some have seen some type of stiations in barrels, but have simply misinterpeted the causation...It was sworn by many that such a gun was at SCI in 1998, but that is not so, only a rumor being lied about to substantiate a claim...

When I talked to Holland and Holland, Rigby, and Westley Richards, there reaction to the question went from a suttle grin to outright laughter...Albiet all agreed that manolithic bullets may or may not, in fact, undo the solder and split the barrels apart and if so then they would do that long before any rifleing poked out the top....