amongst our group we shoot 270wsm's .243. 20-06. whatever gun we feel like shooting. Lots of long range possibilities down there. any of those guns are capable. I'v shot my .243 up to 600 yards... Couse Deer are little deer. like, they can lay down in grass that is 12" tall and completely hide.
we've shot deer from 100 yards out to 550 yards....its Deer hunting
the only difference is they are smaller sized deer, and are masters at escape and evasion.
those deer will lay flat on there bellies and wait for you to walk past, then they'll bust out half way down the mountain before you know it. I would take a long range gun for sure. which, any gun can be put together to shoot long range really. Even the .243. I can shoot 600 yards with my .243 no problem. Any further then that and I'll need a little better scope.
plan on shooting 500yds or less. I know thats a pretty broad spectrum but, that kind of country you can easily shoot twice that distance if your a long range gun enthusiast seeking that kind of thrill.
its just deer hunting, but its in the desert and a deer defiantly smarter that a muley