All depends on what you want to do with that yote. If you just want to kill them I'd say anything 55 and up is good. If your going to use the hide stay under 55. I used to use a .204 with a 40gr vmax and it did wonders.

I'm currently looking into the AR-15 side for a new gun and I think I'm going with the DPMS .223 with a 24" SS fluted barrel. It has a 1-9 twist so I'll have to keep it under 55gr but around here I can't get much past 300 yards.