Recon you could go 338 fed, 308, 70-8. At a push even 6.5PRC and load accordingly. I don't think the PRC will give you much more knock down over a 308 loaded say with 178 ELDX up to 200yd. My choice would be the 308 with 9 or 10 twist and experiment with heavier bullets up to 208gr. Chamber cut...