kansaswiderack,

Out here in the western part of Kansas 250-300 yd shots are not uncommon. I have my 270 sighted in at 2.5" high @ 100 yds and am right on at 250 and still in the kill zone at 300 yds. I use 130 gr Winchester Powerpoints, about as inexpensive as you can get, and haven't had any trouble knocking down a muley. I say stay with what you know. Your loads will be fine.Good luck with your hunt. I have seen some monsters in Eastern Colorado.