"ever see a nice gun with a bulge in one or both of the barrels just in front of where the choke tapers start? this is usually a result of shooting steel shot."
Sure have, once even bulged a chamber personally on a cheap Spanish 12-bore; when, on a dare, I plugged both barrels with 3" 2 oz lead BB magnum loads and pulled both triggers simultaneously. That was quiet a jolt, but the first examples I ever saw were vintage doubles examined long before the advent of steel shot; so swelled/bulged barrels in the forcing cone area of a vintage double gun may, or may not be the result of shooting steel shot loads. But not wishing to give up my double guns for duck shooting when the Feds mandated steel shot for waterfowl in GA, some years ago I decided to find out for myself and determine if all the terrible tales I'd read about shooting steel shot in vintage doubles had any merit; so I conducted my own non-scientific experiment. I took a 1907 vintage A Grade 12-bore Fox gun with rough bores, but nice otherwise, and had a gunsmith open the chambers to 3" and the chokes to light modified; figuring I could afford to risk a $400 gun without too much regret. I then proceeded to shoot a number of Winchester, Rem, and Federal factory 3" steel loads in #2 and #4 size shot thru the barrel tubes. There was no bulging, no ringing, no scoring of even the slightest degree noted; and the recoil of these 3" steel loads was similar to that of a one once skeet load. Frankly I was disappointed, as I had expected the absolute worst. Based on my experience my guess would be that a standard to heavy weight vintage American double gun with its typical thick barrel walls would have little susceptibility to bulging in the forcing cone area; although I would not shoot steel loads thru vintage barrel tubes with tight chokes. Personally I believe your thesis smacks more of rumor than fact; and with all due respect, why would any sane/knowledgeable individual be shooting steel loads thru a set of vintage barrels nowadays given today's other and more suitable alternatives?
