As many coyotes I've seen run off after being hit hard with a 223 I would step up to the larger caliber. Coyotes weigh what? 30 pounds and a wolf is 100 plus maybe 140 or more? I really think those wanting to use a 223 is putting way too much faith in that caliber/bullet combo. Not to say a very well placed shot won't kill them, just that I would want it to drop DRT. The 243 with an 80-90 grain bullet is where I would be looking.