I've prairie dog hunted with a guy who had an AR in .223 that had been worked over. I didn't bench rest test it, but he had and he had no problem hitting prairie dogs out to 400 yards or so pretty consistently. The guy was a great shot and his rifle was as accurate as the Remington 700 in .222 or the CZ in .204 that I was shooting. With enough time, money and skill, you can make an AR do amazing things.

Which is also true of the M1A.