Had a customer put a 308 Win. through a 25-06. It was a Shilen barrel on a Ruger 77. Desroyed the Hogue stock, Ruger floor plate, ejector, and extractor clip. Had to pull the barrel to get the bolt out. Barrel was clear and appeared to be undamaged. He was speckled in the face with small brass bits but otherwise unhurt. Thank God for good safety glasses.
Sewwhat89, Is it possible that you have those two calibers reversed? All of the other stories are about a smaller case in a large chamber blowing up a case, or a large bullet in a smaller bore blowing up the rifle. But the 270 and the 25-06 are basically the same 30-06 case and I don't see how the small bullet in a larger bore would cause the gun to blow-up.