the AR-15 is my preferred coyote gun as well. I have a 16" model that I use when I will be doing a lot of walking and a 20" heavy bull for when I plan to sit and watch for them at a distance. I can't think of a better varmint rifle myself. Well, unless you include my Tikka T3 22-250 - now that is my long range varmint buster there.
"As the light grows dimmer and the trail begins to fade, my sweetest dreams are those of yesteryear, at deer camp." Author, Jim Slinsky