Hello,
I have a Seekins AR-15 lower inbound (yahoo!) and I need an upper for it. I bought a RRA lpk for the stripped lower, but will put in a Geissele DMR or JP trigger soon.
I want to shoot out to 600 yards, so I am thinking a 18-20" barrel with 1:7 or 1:8 twist so to stabilize 77 / 80 gr...