Funny that Rich mentions this particular example, since many years back I was retained on a lawsuit where I suspected (but wasn't able to conclusively prove) that this is exactly what happened. Guy blew up a 270 Wby Mag, and claimed he got a 7mm bullet in a box of .277's, and that caused the blow up. We duplicated the load, using 7mm bullets loaded with IMR4831 in an identical 270 Wby Mag rifle. We fired it several times (with a long lanyard!) and all we got was sticky bolt lift. When I'd examined the guys reloading set up and bench, he had exactly two (2) cans of powder on hand; IMR4831 and IMR3031. Never did try the IMR3031, but I have no doubt that it would have disassembled that rifle exactly like his load did.
Yeah, watch the powders you have within reach, and only one flavor at a time on the bench.