You did not state the use for the rifle. But if accuracy is your main concern then I would look real colse at the Rock River Varminter. Mine is scary accurate. I have owned several Colt's over the years, and I still have three in the vault. Two of them are the Delta Elite's, and they will not even shoot close to the RR. I also owned two Bush Master's. I was not happy with their accuracy so I got rid of both of them.
I never thought I would make an AR15 my go to rifle for the ground hog fields, but I have made my RR varminter my go to rifle for fields under 425 yards long. The rifle is almost automatic at that distance, and shooting double taps is a "HOOT". Tom.