Bro' Drew.
Your photo is not a bulge. It is a rupture. I don't see lifting and bending of the rib in the gunsunlimited picture, but, that doesn't mean it isn't there. Also, an obstruction in a bore is just that, until it isn't. An obstruction that clears miliseconds before yield is met will cause a distortion to some degree, if not a rupture.
Pure arm chair quarterbacking from here in cyberspace. But, interesting, anyway.


Best,
Ted