Gopher Slayer, your way of thinking is correct. When I first got my 300 Win. Mag, I took it calling a couple of times, mostly to get accustomed to the rifle before big game hunting with it, BUT I shot 3 coyotes using 180 partitions, and the damage was no worse than what I often get with my 22-250. With that said, how ever, all the coyotes I hit were broad side shots and I did not hit shoulder. I do beleive that if you hit a coyote facing you, the bullet from your 308 may well go all the way through and leave a gapping hole at the other end, or if you hit shoulder on a 1/4ing to you shot, I'd guess a big exit hole.
If that guns all ya got, hit'em and you will hit 'em hard!!