I've been using the .243 Winchester for coyotes now for about 8 yrs. I shoot the Hornady 58gr. V-Max moly coated factory loads through my Ruger M77 MarkII. I've laid many a coyote low with this combination and have yet to have an exit wound. Only one splatter. Usually just a small entry hole, hard to find, and the vitals look like a bowl of jello. I don't think I've ever lost a coyote or deer to this combination. 90% are DRT (dead right there), never taking another step. I think you will be well pleased with the .243. Very accurate, plenty of ammo choices, and you can find ammo most anywhere. It's a little too much gun for fox and bobcats, but for deer and coyotes it's been a proven winner for me. I give it high recommendations. Good luck.