looked some more and got good news and bad. CMMG is already making an ar for the round. But the bad news is it does take a caliber specific mag and from what there saying mags over 10 rounds are troublesome (visions of a 762x39 ar nightmare I had) I guess at least for me this would be a purely hunting ar and would 99 percent of the time be used with 5 rounders but I do like to play and would like to see at least a 20 rounder work in it.