I don't have a 17 Remington, but I do have a 17 Mach IV. It's only about 300 fps slower. Shooting Starke 25 grain RPVB's, I dropped a nice yote at 140 yards. The lungs were just destroyed. I have yet to shoot at a fox with it, but I'm sure results will be similar.
Oh yeah, no exit wound either!!!!!! As a matter of fact, it's hard to tell where the entrance wound is.