Be advised that revolvers in .45 Colt were once bored for .455" bullets. Late ones are often .452", as with .45 auto ammo.

This accounts for the discrepancy in .45 Colt caliber in my post above and in Alpo's. The bore may be either size, depending on manufacturer and time of manufacture.

SIG P-220's post about the cheap Brazilian .410 amazes me! But I wouldn't try that stuff at home, folks. I wouldn't even try it on Discovery TV. There is a lot of steel in a single shot's chamber. Maybe that explains it. I suspect that a repeatimg shotgun like a Winchester M-42 or the Remington M-870 or M-1100 may have marginal steel thickness in the chambers, which are a part of the barrels. Also, Remington was sued for the quality of the barrels in their shotguns some years ago. They used something called marraging (sp?) steel, which blew faster than better steels if there was any problem, like a bore obstruction. This is my understanding of the matter, based on what was published at the time. A suitable engineer or Remington spokesperson could no doubt explain better. I believe they changed their steel as a result of this class action lawsuit. I have no reason to doubt the safety of my M-870 12 gauge, bought new in 2004.