For predators like fox or bobcat I think the 17HMR is a pretty decent caliber. Using 20gr XTP I doubt you'll get an exit but should drop them pretty quick. I had the opportunity last year to take a coyote at 75m+/-, he was sitting there just looking at me nice and still so a headshot was doable. It took me a bit to find the entrance hole and there was no exit, pretty quick death. The 17HMR is probably a bit light for coyotes if you're forced to shoot the body but they appear to be pretty devastating under 100m on a headshot. 22mag under 100m would also do the trick with very little damage, for that matter a 22lr shooting 40gr solids 75m or less is going to work. I would think most centerfire calibers,even the smaller ones would be a bit much unless you're shooting longer distances.