Raging480,
If your hunting coyotes & bobcats w/your .357, and want to save the pelts, I'd suggest a 158 grn SWCGC or maybe a 125 grn Truncated Cone cast bullet! You can usually get 50 - 100 fps more speed with a cast bullet over a jacketed bullet of the same weight, and the cast bullet won't expand like a JHP and make such a mess out of the hide. Hit them through the "boiler room" and they're dead, take out a shoulder while your at it and they'll go down quicker!
A friend of mine shot a medium size coyote this winter, from 100 yards away with a .243 rifle, and it still ran 50 yards. So nothing is going to put them right down every time.
Your S&W 686 w/a 4X scope sounds like a good way to go, good luck!
Del