WE can solve this quite simply. Those that believe that buckshot, slugs and steel is compatible with full chokes, use steel, 00 buck and slugs through their vintage guns with full chokes for a year and report back to us.
Okay. I shot steel for a couple years in a BSS choked full in the left barrel with no problems. Eventually opened the full to modified because the gun does not have a barrel selector, so I saw no sense in having two different chokes. Worth Matthewson writes in his book,
BIG DECEMBER CANVASBACKS that he used a vintage L C Smith for many years with steel shot before carrying it to a gunsmith for an unrelated problem and finding that it was choked very full in both barrels. Gunsmith found no damage to the barrels from the steel shot.
I have shot 00 buck in full choked shotguns my whole life. Me, and probably 50 other people I could name. Every gun you could imagine. Doubles, singles, pumps, autoloaders, you name it. Not one ring bulge in 40+ years of buckshot through full chokes, sometimes extra-full.
Wouldn't you think that with all that usage there would have been some problems if it were as bad as some make it out to be? Again, I know that full doesn't always give the tightest or best patterns with buckshot or steel, but that wasn't really the issue here was it? My point is that you cannot take every recommendation the ammo and gun manufacturers make as gospel.
SRH