You mention a 650 round magazine. First off, some states might frown on that, after all, 650 is more then 10. Second, all those BB's make one heck of a rattling noise. You will need to practice your calling skills. A tree stand might be to your benefit.
If not, try one of the air-soft guns. The ammo is much quieter. Make sure to get the camo-colored pellets though. The bright colored ones might spook the deer before they are in range.