of the two the 7mm mag has at least potentially a flatter trajectory and more down range energy
most people will not shoot a center fire caliber used for big game often enough too wear out a hunting rifle in a lifetime of hunting
either caliber listed will work, if the correct projectile is selected,
you did not mention the action or barrel length,
you can look up the differences in energy and trajectory, I would suggest you use a 150 grain or heavier bullet for larger game in either caliber rifle
the rifle type may be more important to making a choice than the caliber
I have several very successful friends with 308 win BLR rifles
and while you can get a semi auto, or bolt action, or damn near any action style in either caliber you may prefer one type of action.
https://www.hornady.com/team-hornady...alculators/#!/

https://www.hornady.com/support/load-data/

https://www.hodgdonreloading.com/data/rifle