6.8 Spc Ar
Yep, they are here because I have one.
The brass is hard to get but once you have it all is good.
I have only shot it once, not enough time.
More recoil and a noticeable increase in muzzle blast too.
Fun to shoot I must say.
Talk to Walter at Arms East if you want one, or just the upper, which is the route I took. Quester has the mags too.