Let me add another possible cause of over pressure and a bulge at the point seen. A hang fire can cause something similar. I once had a click-bang hang fire while shooting skeet with a 28 gauge gun, or more accurately, Briley 28 gauge tubes in a 12 gauge Beretta 682. I had reloaded some hulls from a shoot where I had been caught in the rain, and I theorize that one shell still had a drop of water in it that delayed the ignition of the powder until it was at the front of the chamber, where it fully ignited. The result was a ring in the subgauge tube just forward of its joint with the stainless steel chamber. I continued to shoot until the match was finished with the bulged tube with no ill effects. There could be numerous causes for such a delayed ignition, other than a drop of water, but the result is the same, a localized pressure excursion that might be sufficient to cause the damage seen in this case.
Last edited by Tom Martin; 02/06/14 09:00 PM.
