I have a Black Hole weaponry 18inch barrel in 264LBC, with Black Hills 123smk (2415fps)ammo produced for Les Baer,I can get one raggedly hole at 100 yards. With Hornadys 6.5 Grendel ammo 123amax (2440 fps), its very close to 1/2moa. It seems to like my reloads as well, Hornady brass, CCI 450's, 30.3 grains AA2520, 123 smks. Several precision AR builders are using 264LBC over the grendel, 224AR, 6mmBR are also getting more and more popular. Going to chrono some more loads tomorrow and stretch her legs at 300 for group size.
I'm getting exactly the same speed and groups from Hornady out of mine too. Have you tried the Scenars yet?