I'm running a 6.5 Grendel and use Hornady 123gr A-Max with AR-Comp, Lapua Brass, and Wolf Small Rifle Magnum Primers. Dont have the load info in front of me but it is easily 1/2 MOA at 100yds. I tried Sierra 123gr SMK but they shot horrible.
6.5G needs a long COAL and all I could muster was 2.275" but now that I got a couple of PRI Gen3 6.8 Mags they'll let me load to 2.300-2.320". I'm goimg to work up some loads to test this Saturday. I'll post results.
Other powders to try are 8208 XBR and CFE.