There is no inherent difference in a dent and a bulge, except for the extent of it. One is pushed in, the other out. Metal is stretched in both instances. I have repaired both. Dents are much easier, because they're usually much smaller than ring bulges. There is much greater chance for a split to be present with a ring bulge, IMO. I cannot explain what actually occurs when you peen a dent out with repetitive light hammer pecks, not being an engineer or well versed in metallurgy, but it appears the metal "flows" back into nearly the original dimensional state. The only bulge I ever removed was a ring bulge that was about 10" from the muzzle on the right barrel of a 30" set. I knew I couldn't get it all, because it extended all the way around and was, obviously, under the ribs as well. After several sessions of peening, the top rib popped loose. This necessitated the complete removal of top and bottom ribs, and facilitated a more complete removal of the rest of the bulge. However, it was then found to have a split in the section of the bulge between the barrels, which was tig welded.
Bulges are bad news and, IMO, must be evaluated individually. The bulge I removed was what I would call a severe ring bulge, with much metal displacement ............thus, the split. I would never consider shooting, or repairing, one anywhere near the breech, and it would have to be a very "mild" one even then.
SRH
Last edited by Stan; 02/24/18 08:12 AM.
