I had the opportunity last week to test the new line of AR's built by the Bushmaster Custom Shop at Camp Butner and must say that I am impressed. The three rifles, the Urban Interdiction Rifle (UIR), the Perimeter Security Rifle (PSR), and the Precision Marksman Rifle (PMR) all held sub minute groups out to 600 yards with Black Hills 68, 69, 75 and 77 grain ammo. The best group shot at 300 yards came in at 7/8" with 75gr and at 600 the best group was 2 1/2" also shot with 75gr! The weapons were shot from a bipod in the prone, not a machine rest. I never thought you could get that kind of accuracy out of an AR. Check out the website at
http://www.bushmaster.com/bcs/