I have several welded bbls, both twist & Damascus which I throughly enjoy using. I have one twist bbl gun I do "NOT" shoot. It is an H grade Lefever & has a crack in the left bbl a little ahead of the forend. It appeared to be the result of being hit on a sharp corner & dented in & subsequently fired. The crack is radial about ¼" long. One side was still turned inward toward the bore but the other side was flared outward so that one could simply look through into the bore. I had bought it very cheap as a parts gun. As the bbls were essentially worthless anyway, also badly pitted, I decided to "Test" it a little & fully expected to blow it further. I ran my expanding dent plug down the bore & raised the dented in portion & hammered down the outward portion till the crack was actually difficult to see at all. I then proceded to fire "REMOTELY" several factury 3¼-1 1/8 loads through it with no visible effect. I then ran a number of 3 3/4-1¼ factory High Velocity loads through it, again no visible results. I then put some 1 3/8 oz reloads through it, though these were lower vrlocity & may have had less pressure than the factory High Brass. After all this nothing, didn't even see any soot make it outside the bbls. "But" I know that crack is there & still wouldn't put my hand out there & shoot it.
I do fully believe that unless a bbl bursts in the chamber the odds are extremely high it had an obstruction in it. I also fully believe it is an old wives tale a damascus bbl will "UnWind".
Generally speaking I think the Yield point of a damascus bbl is lower in proportion to its ultimate strength than that of a steel bbl. This would result in more bulging & stretching of the metal prior to actual burst in the damascus, thus giving a different appearence. I think though that unwinding bit is mostly myth.
