I've killed them with everything from a 22LR to a 270. Most of the ones I've killed here in Kentucky have been with a 223, and my longest kill was about 450 yards. I like a 50 VMax handloaded to 3400 fps. I mostly use the 223 because I'm also hunting bobcats when I'm calling and it's much more fur friendly than anything else I shoot. Now, lately I've been shooting a 22-250 with a 40 grain BT, and I'm starting to feel a lot of love for it. But......if I were strictly coyote hunting and doing it for business, not for fun, I'd pick a 243. It is just a better killer, and I use bullets from 58 to 85 grains, and it doesn't matter which one, although it is very hard to beat a 85 grain Sierra.