I don't consider myself a long range shooter, however if the situation and conditions allowI willtake the shot on game to 500(ish).I do not have a biggame rifle that has over 10x. I used to have more power but found the type of hunting I do the more power wasn't useful, except on the range. JMO but when I'm at the range I try to mimic hunting situations, so if in the field I'll only go or use 9 or 10x for the shot why would I move to 12, 14, etc on paper? Also the majority of my shots while hunting are under 300 yardsbutwhen I do have the longer shots I have practiced with my scope and power settingto be proficent with it. I also don't like AO's on a big game rifle. Another thing to consider is the higher the mag or power the more critical the optics, simply put you need to pay to harness the potential. I'd rather put the extra money for more power to a better optical in general with less x or mm's. Just my way of thinking though.

I'll second the z600 3x9x40 zeiss conquest, that's what I have on my 338wm. Nicecombo.

Whatever you do for glass don't skimp on mounts, get yourself a quality set of ring/bases. I can recommend Warne Maxima's, Talley's & Leupold double dovetails, all 3 have performed well for me under tough hunting conditions. My preference right now would be the either of the first 2 though.