That let go at the breech.
Look at the shell.
Look how thin the chamber wall is at the rib.....one of the most important places we cannot measure wall thickness.
Look how compromised the chamber to rib solder is.....it is black and crumbly, looking just like the little chunk missing about half way down the chamber I bet that was there a while...little chunk or pit let go, eat solder from inside out and after some time.....boom.

I see no ring bulge, I see the back of the chamber letting go and peeling the barrel forward.....not saying for sure it was not obstructed but that was going to go....sooner not later.



Ms. Raven