300Blackout blowout

Had a major rifle malfunction on the range today.  300 Blackout, in a rifle I have several hundred rounds through, failed to fire.  Firing pin wasn't even touching the primer.  A group together tried to diagnose the problem.

As a last resort, I swapped the bolt carrier group from another rifle.  The rifle fired, and the round blew out of battery?  It blew the magazine out the bottom of the rifle, and peppered the watchers with powder.  When I got home and dis-assembled, the problem was even worse than I thought.

BCG stuck partially out of battery

Extractor bent

Barrel bushing? Cracked through

Cartridge (minus base) stuck in barrel.  Bullet is still 3/4 down the barrel also

Even the upper receiver is cracked through