I've shot a single whitetail buck with the 270 grain .375 H&H load, and while it is not much of a "test", it worked pretty damn good.

The 5x5 buck unfortunately turned just as the trigger broke, resulting in a JeffO bullseye shot. The failsafe shed all 4 petals, and came to rest against the skin in front of the brisket. It didn't damage as much hind quarter meat as I feared it was going to, and put that buck on the ground INSTANTLY.