Very interesting if you look at the pictures, It was the action, not the barrel or bolt that let go, and in spectacular fashion, Glad He's alright. Scope split in half!!! If the bolt had not held, this man would be in a world of hurt. I have a good friend who bought a high end semi/custom rifle in a proprietary cartridge (( big stuff )) that let go, after much mongering and my friend losing some sight in one eye, it was settled for an undisclosed amount

You would be surprised at the manufacturer.
These kinds of things happen, I had a young man bring me a Savage model 99 to sight in for him, you learn quick on the gunsmith bench at a public shooting range to match the ammo to the gun. He laid down a .308 win, rifle and gave me a box of .300 savage to sight it in with. I asked him if the rifle had been rechambered, he said no, I then told him he had the wrong ammo for the rifle, he then explained that this was a Savage rifle and this was the correct ammo, and he had killed deer with it twice before. We discussed it for a minute and he was not budging, I said hang on a minute, and went into the stock room and brought out a box of .308, loaded 5 rounds in the rifle and cycled the action and they all chambered and ejected. I then showed him the difference in the 2 cartridges, mostly length, he was getting a little glow in the cranium, when I asked him if he had any of the rounds he had already shot, he said yes, and I said bring me one, of course the .300 Savage fired in a .308 win chamber was damn near a straight wall case. I sighted his rifle with the correct ammo, and low and behold, had a 3 shot clover leaf, under 5/8", I said do you want to sell this rifle and he just said, " give me that " Live and learn.
Lesson, if you bring more than one caliber that will somewhat interchange, be very careful. use paint on the case heads if you need to, something to catch your eye, when loading. A bloody face beats the loss of an eye or worse everytime.