For you few AR fans out there, you have not lived, until you have spent some time in a PD town with an AR. I have a BM XM15 that sees a lot of duty against PDogs. I have been shooting PD's for a long time, but only the last year or so, with an AR. The reaction that I usually get from guys is "yea, you want to set up and spray away". These guys have no knowledge of AR's, or how quickly that you can make follow up shots, even at long distances. I routinely make follow-up shots on wounded ones, or on second or third dogs that take to running. With my long legged Harris BP, I usually walk to a good vantage point, and set up in a sitting position. The BM is extremely lethal. My gun loves the 52 Grain A-Max, and even though it is designed to be an "accuracy" bullet, it is great on the PD's. A good trigger, and good optics, and you are set.
For me, the AR works much better than the 22-250 and 220 Swifts that I have shot, as it is easy to see the shot. For me, this paramount to my shooting pleasure, being able to see exactly what happened at the target. Also, I find that the lighter and slower 223 bullet may drop a bit more than a 22-250, but that is why they make target scopes. Grab a few clicks, and you are in business, way out there. With my chrome lined barrel, I do not worry about over heating, or throat erosion, or the other issues associated with the 22-250 or Swift. It is also pretty darn handy to grab a couple of spare mags as opposed to filling my pockets with 22-250's.
I can also slip the old 22 LR conversion in, and shoot at dogs that are in a more restrictive area. This helps with some ranchers, who do not want "big bores" shot around buildings, equipment, or cattle. All in all, it is good practice for when I will get to go big game hunting with my 458 Socom.
For any of you that are serious about getting into Varmint hunting, The Varmint Hunters Association cannot be beat. Superb magazine that comes out 6 times a year, full of how to's, where to's, and occasionally an AR article.
I have not yet tried my AR with Coyotes, but my experience with PD's leads me to believe that it will work extremely well. For PD's, the AR15 is my cats meow.
Craig in NM