Using advice from some very knowledgeable AR-15 geeks, I bought a Double Star lower to build my AR-15 varmint rifle. Or better put, had one of the AR geeks build it for me. I did put in a Chip McCormick trigger. As far as the upper goes, just bought a complete Model 1 with a 24" ER Shaw match barrel. It has all put doomed my other varmint guns to the safe from now on. Oh, dont get me wrong, I love my bolt guns, but boy howdy, will that AR shoot! I have shot TWENTY shot groups in the half inch range at 100 yards. What more do you need? I will put up with having to chase after my brass for this kind of performance. Color me happy.