I'm running the Mark AR Mod I 3x9-40 Mil dot, I had leupold cut some turrets for me with the zero stop and I will just say how happy i am with the results. took it out on steel from 300 yds to 700 yds and it smacks the plates pretty dang hard and fast, even with my bad eye's i had no problem seeing things ...
The glass is pretty dang good... JMO but for a coyote rifle the 3x9 should be plenty, I think the 6x18 is way over kill unless you plan on shootin varmints with it...