I'd say 243 but I can't get myself to purchase one with a 1-10" twist, so it'd be 7mm08 all the way.
Actually, the 223 would be a good way to roll.
What would be your load of choice in 223 for Whitetails, and do you have as much confidence in it as something like an 80grn TTSX or 85grn Game king in a 243?
