I try and avoid recommending specific rifles for coyote. Just too many variables and too much personal preference involved. I will say, for myself, in a factory chambering, I like the .22-250 for coyote. And I'm a turn bolt guy. But, if someone else wants to go to town on them with an AR platform, that's great too!
But as far as chambering selection for coyote, I'm a huge fan of chamberings that shoot EXTREMELY flat. More flat than can easily be had in any off the shelf factory chambering.
To me though, the "main thing" with a coyote rig, is how it fits and handles. Having a triple or even a five pack running over the caller and not wanting to let any of them leave turns into some fast action, fast target aquisition, your rifle better feel right in your hands or you're gonna look stupid in a few seconds kind of action.
So choose a rifle that feels right in your hands, shoulders quickly and naturally and just has the crosshairs painted where you want them almost automatically.
My "main squeeze" on stand for quite a few years now has been my .17 Predator. Which is a necked down, blown out .223 with the shoulder moved forward for increased capacity. My working load has 30 grain bullets moving out at about 4100 fps. Extremely flat shooting, no recoil - I see every shot through the scope, superbly accurate and folds up coyotes like cheap lawn chairs. Here is a picture of my .17P after it's first morning afield.
This year though, just for grins, I've been campaigning a 6-284 launching 55 NBT's at a hair under 4300 fps. Shoots even flatter than the .17P, just as accurate, but hits a lot harder (kinda hard on fur...). Here is what it did on it's first full day afield a couple months ago:
Anyway... My opinion, pick something flat shooting - a .17 Rem, .22-250, Swift, .204 or .243, then get it in a rifle that fits and handles for YOU.
- Dave