Whichever one is heaviest.
Bring first-aid supplies for facial wounds caused by the scope.
Pretty funny right there. Even funnier would be to compare the same bullet in a 308, 30-06, and 300 WM and see whatcha "get" for the punishment.
Isn't it something like a 308 at 300 is a 30-06 at 400 and a 300WM at 500, but 90% of BG are taken at 200?