I have a friend that shoots the hot core out of a 270win and I haven't seen a deer or elk shrug one of. Also haven't seen it take more than one hit. He's shot elk from 50yrds to just under 500yrds with it, I have even grabbed it and dropped a few animals when I had a gun problem.
So far as I know only one elk didn't have an exit wound and that was a big cow last year at 50yrds, turned her insides to goo, everything else has had and exit wound.