What Caliber for a Steyr Scout?

I'm wanting to get a Steyr Scout rifle but I'm unsure over what caliber I want for it. I know that they come in .223 (5.56 NATO), .243 Win, 7mm-08 Rem and .308 Win(.762 NATO) and I'm looking for the best one that still has the power to blow through bone, but is still able to do that with a long distance shot. I'll be shooting at 300-400 Meters at the least.