RE: 300 win mag vs 7mm Rem mag for deer/elk
To be perfectly honest you may as well flip a coin. The dead deer, elk, caribou, or moose will never know the difference.
The 7 will have slightly less recoil (maybe 3 or 4 foot pounds) with equal weight rifles, the trajectories will be about identical with similar weight bullets for caliber (180 - 30 cal & 160 - 7mm), penetration will be a wash also. There are tons of factory loads available for both as well as tons of bullets for the reloader for both. Price will be the same for either one with the same bullets.