Ah, the image of a bird roasting in the oven with the stuffing filling the cavity is an image we got from Norman Rockwell, but not from any properly roasted turkey.

It all has to do to with Mass and Moisture. Roasting a turkey is not rocket science, it's actually one of the easiest "big production" meals to do. The ultimate goal is a properly cooked turkey (165 degrees internal temp according to the FDA) without overcooking and ending up with dry meat. When you add stuffing to the body cavitiy, you are adding mass, which means a longer cooking time for mr bird, which increases the "dryness" result. Traditional stuffing is also a "turkey juice" sponge, so during that longer cooking time, the stuffing gets moist from the internal moisture that should have been in the meat. Cook the stuffing in a casserole dish or stovetop and, if you have to, spoon it into the bird for the "Kodak Moment."

Also . . NO BASTING! Put that bulb syringe away for artificial insemination, you don't need it for the turkey. Turkey skin is waterproof, so you're not adding flavor to the meat, but you are letting heat out of the oven which will increase cooking time, which will result in dryer meat. Starting out with a high cooking temp to brown the outside of the breast will color and crisp up the skin and seal in the moisture, then lowering the oven temp will finish the internals. Don't be a baster.