Hard to beat an 30-06, 300 win, or 7mm mag. Figure out how much you want to spend, then look at what the major manufactures offer in that range, almost any new ruger, remington, browning, tikka, savage, etc... shoot better than most need. Get stainless synthetic if your hunting in the mountains, and don't skimp on the scope, you should have as much or more into the scope than the gun itself. Good glass is a must, especially if your hunting the wide open western country. A scope with multiple aiming points on the recticle, and some practice makes shots out to 500 a lot easier.