Back to the bulges, I wonder sometimes if they were not perhaps the result of a buffered load using 'cream of wheat' or flour or ? There is a growing body of empirical evidence that the use of kapok as as filler in reduced loads in some single shot rifles may have caused some 'ringing' in front of the chamber throat and I have read that some of the older or previously recommended fillers for shotshell loads [flour/corn meal/cream of wheat] are now specifically NOT to be used.
FWIW, I own a 28" bbl'd O/U 28 with a slight bulge some 22" up its lower bbl. The 'incident' occured while the gun was on loan and I only know that it supposedly was not shot with reloads, but it WAS fed some old paper hulled cartridges. I supect some may have been reloads anyway, but who knows? I also have to wonder if a piece of fluff [old insular stuffing] from a gun case or even a cleaning patch was not inadvertently left in the bore. I know of folks that will poke a piece of paper towel or a napkin through a bore and I also suspect that there have been times when someone inadvertently placed a shell in a gun from their bag in the field and may have poked a piece of tissue or some other 'something' in the chamber in front of the cartridge without even realizing it .. a 'heat of the battle' kind of situation. Just not paying attention. I know that I get feathers in my field bags with the cartridges sometimes and I am annal about picking stuff up found in the field too and I have been guilty of putting it in the same belt bag with my cartridges. I've had lip balm, extra ear plugs, candy wrappers, dog 'treats', etc in my cartridge bag at one time or another in the field and I would suspect so have many others. Just some idle thots on the 'causal' part of bulges. Obviously something has played the role, on ocassion.
