To expand on what Pawildmanstated, basically the 7mm-08 has less case capacity than the 7mm Rem. Mag. The -08 will thus have lower velocities due to less case capacities so it probably won't fly as flat as the Mag nor deliver as much energy. How much difference? Not that much, 200 fps or so, and about the same less energy. For deer it won't matter, for elk it will only matter if you're shooting out past 200 yards or further, and even then probably won't really matter. Drop would likely be around 2-3 inches lower at 300 yards.

If you plan to hunt just deer this is the perfect round. For larger game you might look at the Mag. ora larger caliber (but I love my 7mm Rem. Mag. so you can't go wrong with a good 7mm in any case size).