Bro. Buzz: I only play a metallurgist on the internet, but have been told by several smiths that ANY defect near the chamber/forcing cones makes the barrels unusable and unrepairable.
Then again
Experts on Guns and Shooting, George Teasdale Teasdale-Buckell, 1900
http://books.google.com/books?id=4xRmHkr7Lp8C&pg=PA373&dq On the subject of steel v. Damascus, Mr Stephen Grant is very clear, and much prefers Damascus for hard working guns. He related an anecdote of one of his patrons, whose keeper stupidly put a 12-bore cartridge into his masters gun without knowing that he had previously inserted a 20-case, which had stuffed up the barrel. Fortunately, no burst occurred, but a big bulge, which, however, Mr Grant hammered down, and the gun is now as good as ever.
