The Military is now using the M16/AR15 for it's High Power competition. If you're unfamiliar, that is out to 600 yards. With the advent of VLD bullet technology, I think they're starting to play with this rifle out to 1000yds, although I would think I would run out of windage on the rear sight before too long on a windy day...
The rifle can be tuned to sub minute accuracy, which means bye-bye gophers, prairie dogs and woodchucks out to 200 yards or more with a good scope and position.
As a Marine, I HAVE to use this rifle. I prefer the M14 or even the M1 Garand as a High Power competition rifle, but when every one else has transitioned over to the Black rifle (for Matches), we had to follow suit. The Army teams had about a 4 year head start, and we're just now starting to be competitive again. Don't sell the AR out just yet, I think you'll do fine with it.
Incidentally, I use Carb Cleaner to clean out the gas tube, and a bunch of long, wooden Q-tips to get into all the nooks and crannys in the chamber area. These cleaners leave a white residue on the parkerizing, but a light coat of CLP or equivalent keeps everything looking good and protected.
Hold in the Ten ring!