Re: What the heck happened here...???
The barrel looks to be intact no bulge, no obstruction. An obstructed barrel would cause a very different explosion and would not explain why the base of the case blew out. It was a remington stock gun with factory remington ammo. The gun was shooting off the bench at a range and previous shots were fine and the round immediately preceding went bang with no hint of problems. Everything is going back to remington. I agree that the problem seems to be with this single round (wrong powder, spiked). I just wanted to see if anyone had an issue like this before or could at least tell me what exactly happened according to the laws of pressure.
On another note, I had the polymer tips falling off a box of winchester 7mm silvertips. Unexplained flyers were suddenly explained. Never shot factory ammo again. Likely never will again.