Lloyd - it depends a great deal on the location of the bulge. A small bulge toward the muzzle where the pressure is low is not hard to repair. I don't think any barrel specialist would attempt a bulge repair near the chamber or proximal 1/3 of the barrel.
OTOH
Experts on Guns and Shooting, George Teasdale Teasdale-Buckell, 1900
http://books.google.com/books?id=4xRmHkr7Lp8C&pg=PA373&dqOn 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.
Craig makes a good point.
Thinned barrels usually just split, where they are most thin, which is usually the lateral wall - .018" here after "inexpert" honing to .739"
Obstructional bursts can be asymmetric if the wall is supported somewhat by adjacent metal, but the terminal burst will again be where the wall is most thin
A Parker 10g with what was very likely a wad in the forcing cone, with an asymmetric bulge, and lateral terminal burst. The inferior wall of the chamber was of course supported by the hook assembly
