I'm relaying the following from an email a friend sent me that was sent to him. I don't know any of the parties involved....it could be all BS...except for the exploding gun part.
Apparently the hunter was using Brenneke KO slugs. He fired twice, with no issues on the first shot but the second shot resulted in this catastrophic failure.
It was reported that a local gun shop owner called his Remington rep regarding this and the rep stated that they have had a 'rash' of barrel explosions recently due to Brenneke slugs. Supposedly Brenneke had changed their production process whereby they are gluing the wad to the slug. The wad and slug separate leaving the wad in the barrel. The obstruction causes the catastrophic failure on the next shot.
Apparently, Remington will be replacing the gun.