7mm mag is a lot of rifle for deer, but it really depends on what species of deer you are hunting.
Whitetail, too much gun in my opinion. Your going to damage meat if you hit shoulder I would aim for the neck. Moose, I would feel confident in shooting a moose with a 7mm mag. Any species in between them is going to be takeable with 7mm mag.
My opinion is that your 7mm mag would be adequate to kill any game in North America but in many cases it is going to be overkill for anything under 250lbs.
If you are sighting in your 7 mag out in the woods, FIRE INTO A HILL! You can punch through a 5" tree trunk, knock the tree over, and it just keeps on going.