"He is starting to get into hunting out here in Colorado and beginning to realize that mountain hunting is a tough game."
You don't mention his experience in hunting/shooting prior to moving(?) to Colorado. Unless he has shot a 300 WM a bit and is comfortable with the recoil and thinks he can handle the increased recoil of an even lighter rifle in 300 WM... I would look at the oft mentioned alternatives; 30-06, 308, & 7-08.
I HAD a 6.1 pound 300 WM (bare rifle weight) and really liked the combination, but the recoil was quite snappy and after several years asked myself why deal with the unnecessary recoil when an '06, or 308 would suffice for everything I need to do (Deer, Elk & Bear). I enjoy shooting them a hell of a lot more, hence find myself at the range playing with them more than I ever shot my 300 WM.
YMMV
Jerry
