The vast majority of coyote hunters use .22 centerfires, like the .222, .223. and .22-250. I use a .223 myself. Out to 300 yards, it is hard to beat. It shoots flat and delivers enough energy and enough lead to get the job done effectively. Most of my shots fall under 100 yds, and I've never hada bullet exit. Nearly any good bolt action rifle topped with a quaility scope will serve you well.