Varmints get 257 Bob and under.
Whitetail get 243 to 30-06
Elk, black bear, and Moose get 270WSM or 308 or bigger
Grizzles get 8mm Mauser or bigger.
The Big Five get 375 H&H or larger, by most laws.
I save the 50 BMG for squirrels and the 950JDJ for snakes o_O