Page 102 - Turkey Book from Meathead

So 325°F is a nice compromise. High enough to benefit from the Maillard reaction on the skin and melt some of the fat, hot enough to gelatinize connective tissues, but not flamethrower hot, not risking a badly overheated meat exterior before the center is cooked.
If you have a smoker or grill that doesn't get to 325°F (some smokers won't, especially most gassers and electrics), you will need to cook longer. Don't sweat it. The skin should still be brown because the Maillard reaction can still take place at lower temps, but at a much slower pace. Besides, the smoke is going to darken things, too. But you may not get really crispy skin. If the skin isn't crisp by the time the meat hits 150°F, put it in an indoor oven or on a grill at 350 to 400°F.