I used a 243 during the fur boom of the 70's -mid 80's.I shot alot of fox using sierra 85 gr.match bthp.If you hit them behind the shoulder you get a quarter size exit.The match bullets are tough and dont open up much.I shot 14 fox in two days with 243 hornady 80 gr. fmc and only a pin hole on each side.I had to finish them with my 22 pistol as when I went to pick them up they would get up and run.I only lost one fox down a hole using fmc,but if I hadnt had a 22 I would of had to finish them with the 243.If you hit bone with any 243 round your going to blow up a fox.If your a good shot youl be fine,if your not your stories will sound like the negative 243 stories you hear.Also never shoot a coyote with a full metal case,you will be lucky to find him.