Isaac,
You could screw around with this forever. I only own one AR and it's a RRA M4 6.8. I wanted it for the same reasons as you. I went out and bought it before the election because I could see this mess coming. There is a gun shop by me that specializes in AR style rifles. I bought a ARMS 40L for a BUIS and Leupold Mark IV super high aluminum rings per their recommendations. Put a Leupold Vari-X III in 1.75-6 on it that I happened to have laying around. It came with the two stage match trigger also. This out of the box setup shoots MOA at 200 meters no problem using Silver State Armory 6.8 110 Pro Hunters and 110 TSX. My cousin is one of the biggest ranchers in SD. He liked mine so much he got one himself for a truck gun. He couldn't find a RRA but I checked around and found him a Bushmaster. The Bushy shoots just as good as the RRA. The coyote and deer population has seen a marked decrease on his ranch since then. Someday I might buy a 5.56 upper for it but for now I figure why? The 6.8 hits a lot harder than the 5.56 and I don't plan on vacationing in Iraq or Afghanistan any time soon. BTW if you get a 6.8 get the PRI magazines. They cost more but are well worth it. Another thing is that Silver State Armory requires a Spec II chamber, 1-10 twist, six groove barrel for their combat loads which run 100 fps faster than their commercial loads.
