Belt Fed
SAINT
Yep, it does sound like you had a squibb and the next round blew the squibb out and bulged the barrel where they met. kinda weird though that all the rifling is gone.Not obstructed -- round #17 from the third 18 round magazine was the squib. The case is still firmly attached inside, and the slide is back about 1½" -- the case is wrinkled, the LGS gunsmith said the barrel had ballooned and he verified via borescope that the barrel was toast, had no rifling and the case was not a live round.