I can't help you with the .17 Remington loads, but I do know that the .17 Mach IV works very well on coyotes. I've only taken 3 this winter, out to about 225yds, but it drops them as well as the larger varmint rounds. The .17 Mach IV out of a 20 in TC Carbine barrel makes very near the same velocity as the .17 Remington, if there is any difference at all, and burns a less powder and throat. I've had very good luck in my early experimentation with the 25gr Bergers.