I've had good luck with my 458 SOCOM in the AR15 platform, shoot 325 gr Hornady FTX and 500 gr round nose subsonic. However, I am mostly hunting brush country on foot with few shots over 100 yds.
I'm still working on the handload for my Christensen Arms Ridgeline in 6.5x284 but preliminary results show it should be around .5 MOA or less and it's 6.5 pounds before optics.