I have had really good success with a Bushnell 3200 2.5-10x50. I got it on another gun in a trade and figured the 50mm objective wasn't a disadvantage in mounting height with the Burris PEPR mount I use on the AR. The low end is good for quick shots, the high end is good for longer ones. The zoom dial turns really easy too so that I can adjust power fast with one hand. I really don't often pack my AR if I expect shots past 250yds to be likely. I personally prefer the more powerful bolt gun with a higher BC bullet at a higher velocity for that. At least until I get a 22 Nosler upper.
Another AR scope I've used with some success is the 3.5-10x40 Leupold VX3 with the Boone & Crockett reticle. It fits the trajectory of my 55gr load from my 20" barrel better than the VH reticle. It still isn't perfect, but if I zero the 300yd crosshair at 300yds it gets me on a coyote to there.
The bolt gun (243 win) has a Leupold VX-6 3-18x44 with the TMOA reticle. I would consider that scope about ideal for coyotes. It has awesome glass, an awesome field of view, and plenty of zoom. I would call that my perfect coyote scope except that the turret has issues returning to zero after dialing elevation. I now just zero it for my max point blank range and don't dial it, works fine. Coyotes seldom give me time to range and dial, or to go prone anyway. If the new versions have perfected internals I'd think they are ideal.
