Disclaimer: I'm in the small fields and bottomlands of Tennessee, so it's a bit different hunting coyotes here. We don't have to worry about long shots when calling them in, and I've managed to get most of my coyotes under 100 yards. I've been hunting with a 12" 327 Federal Magnum Encore, and I've taken a 12" 221 Fireball with me at some points. No kills with either yet, though. I've killed a deer with that 327, so it's a definite crossover cartridge. The Fireball, while otherwise great, is decidedly not.

If I was designing, say, an Encore handgun to use for both deer and coyotes, I'd make a 15" barreled 257 Roberts. Plenty of power for deer even out of the short barrel, and would definitely flatten any coyote with light bullets. Alternatively, a Contender chambered in 25-35 Winchester. I have heard of a 257 Weatherby chambered Encore, no doubt a custom barrel.