I have a 12 ga single shot Bay State shotgun that had a bulged barrel about 3" from the muzzle. I had it bobbed and the bead replaced by Mike Orlen a couple of years ago. Since then it has been my trial gun for odd cartridge combinations I come up with, including 2.75" steel shells in both 7 and size 3 shot at about 10,500 psi (per published BP loads). So far no effect at all has been observed on the interior of the barrel.
And Bay State ceased to exist as a corporate entity in 1908.
Steel target loads have thicker petals than do lead target loads...
Mergus