Personally I am not a fan of a semi auto. Over the years the semi auto has been the most troublesome type of action I have observed. . Here in Colorado you may get warm dry weather or extremely cold & wet. Below freezing. Semi auto's are the most prone to failure in cold wet conditions. If you absolutely have to have a semi auto extra precautions need to be taken to insure proper function in inclement weather. As to caliber any thing from a 6.5 up with the proper bullet properly placed will work fine. The bolt action is a simple dependable type of action & would be my first recommendation.
