Always use expanding bullets on live animals, even a lowly coyote deserves a humane ah-de-ose. thats as close as I could spell it anyhow). But as a rule you should allways check your zero any time you change ammo. It's a good idea to find one load of one brand and stick with it, you may even find a shift in point of impact from one box to the next. So don't take nothing for granted, send a few downrange just to make sure!