Are you going to be shooting competition where you are limited to the 223 308 cartridges. Both can frustrate starting around 500 meters and out. If it is available then a 6br 6 creed or 6.5 creed are much better options to start tagging x's at that range. If you are a 100 yard shooter then the 223/308 are just fine.

I would make a trip to the range and see what the other guys are shooting. Ask around about the availability of ammo or reloading components.