Please rethink the 6.8spl. I was talking to friend which is a AR builder for a gun shop.He was telling me they were going to build a few uppers for several cal. for an upcomming gun show.When ordering barrels he found out that all barrel manuf. have quit production on all 6.8 barrels. They told him the 300 blackout is becomming so popular the 6.8 is going by the wayside. 300 blackout ammo is alot cheaper than the 6.8 and to change a AR in 223/5.56 to 300 blackout all there is is a barrel swap.Uses same mags and all.Changing to a 6.8 is more costly all the way around ammo and all.