Or you could go a little nuts and go with an AR-10 variance with all the long range cartridges there are for it. You can then go with a 6.5creed or a 260rem and really reach out and smack some coyotes if the need arises and either would be good deer medicine for close or far off. If you are stuck on 15 though, I have .223, 6.8spc (2 of them with dad's old one) and dad's .458socom. As Nomercy said, the 6.8 would get my nod over all of them for your needs but the .458 sure does slap a hog into the dirt post haste. I don't think he ever grease spotted a coyote with it though he did behead a squirrel that was pissing him off with it.