Howdy! My first post here!
Only shotgun barrel I've seen blown open was a Remington 1100 12 ga with some dirt in the muzzle. Rough quail country in So Texas. Friend hacksawed it to just behind the "petals" and proceeded to have a very good hunt with cylinder bore 12 ga.
I have been shooting smokeless in my damascus barrels a long time. Like so many, my loads are quite a bit lower pressure than black powder! 1 oz of shot over any good plastic wad, over 19 grns of IMR PB powder gives right at 1159 fps at right at 5K psi pressure.
So I wonder...to get that velocity, the pressure must stay up much longer. So the higher pressure is not at the breech, but somewhere forward, where pressure behind the remaining. If it were gonna burst at this pressure, it would do so where barrel steel gets pretty thin; up around feft-hand position.
