Preheat your smoker to 225°F (107°C).
Pat the turkey dry with paper towels and season generously with kosher salt, inside and out.
In a small bowl, mix together black pepper, paprika, garlic powder, and onion powder.
Rub the softened butter under the skin of the turkey, then rub the spice mixture all over the turkey.
Place the turkey on a smoker rack and insert a meat thermometer into the thickest part of the breast without touching bone.
Add the soaked wood chips to the smoker, and smoke the turkey at 225°F (107°C) for about 6 hours or until the internal temperature reaches 165°F (74°C).
Remove the turkey from the smoker and let it rest for 30 minutes before carving.