My go to rub for pulled pork is The Renowned Mr. Brown.
1/4 cup Black Pepper, fresh cracked
1/4 cup Paprika
1 /4 cup Turbinado Sugar (Raw Sugar) or Brown Sugar
2 Tbsp. Salt, Kosher
2 tsp. Mustard, dry
1 tsp. Cayenne pepper
(Makes enough for at least an 8 lb. Boston Butt)
It develops a nice thick flavorful bark. The turbinado sugar works better than brown sugar. If you don't have cracked pepper, or a way to grind whole peppercorns to cracked pepper, you can use regular ground black pepper, but cut down on the amount or the pulled pork will be a little too peppery. I like to apply the rub the night before, wrapping it tightly in plastic wrap. Then place it on a rimmed sheet pan, and into the refrigerate. About an hour prior to placing it in the smoker, I take it out of the refrigerator, and often give it another application of rub, before placing it into the smoker.