Can you guess what caused this failure?

Bore obstruction bore obstruction bore obstruction. Pressure in the chamber from a wrong powder would have opened up the part behind the barrel.
I agree, I had an over pressure fire forming 280ai once, destroyed the bolt and welded the case around the bolt face. Replaced bolt (k98) and had gunsmith check the rest out. Only destroyed the bolt, never fireformed with Unique again!
 
I know a guy who used to live in the north east Alabama area, won't say his name. He moved to Kansas for big White tails and started a semi guide business to go with his farming. Anyway, a friend asked to borrow his inline muzzle loader which he gladly did. He even loaded it for him. The guy brought it back after the hunt that nothing was taken,and clyde, not his name took it outside his house to unload it. Put a 209 primer cap on and pulled the trigger. He lost 2 fingers on his left hand from the explosion. The guy he loaned it to also loaded it without telling him. Neither knew it had be loaded other than Clyde the first time, that he failed to tell his friend it was loaded and his friend had failed to tell him he had loaded it. Communication, its a wonderful thing.
 
I know a kid who bailed out of a muddy truck to shoot at a buck back in the late 80's. He had mud from the floor board in the end of his 30-06.

It split from the end back and made a big Y.
he was fine except for a massive black bruise on his shoulder.
 
There were some pictures of fluted sako A7s floating around the interweb with barrels that looked like that.... Split in the flutes & bird caged. The word on them was that some bad barrels that got out of the factory were the cause. Who knows. Ultimately, it's always more pressure than the barrel can handle that causes it. Simple question, simple answer.
 
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