Absolutely doable and that level of accuracy is exhibited regularly at XTC and LR matches. I'm classified as Master and have shot 100-9x with an AR service rifle on the 600 yd slow fire XTC target which I believe has a 1 MOA X-ring (6"). I've also managed 10 x's at 1000yds in Palma competition which is a .308 with aperture sights. Probably rare to achieve with a service grade rifle, but not beyond possibility.
