Carolina Pulled Pork Sandwiches

Vigorously whisk together vinegar, ketchup, brown sugar, Worcestershire, crushed red pepper, and mustard in a medium bowl until sugar dissolves. Measure 1/2 cup sauce into a small bowl; reserve for slow cooker. Cover remaining sauce (about 2 cups) in medium bowl; set aside for serving.

Pat pork dry with paper towels. Stir together pimenton, brown sugar, salt, mustard, onion powder, celery salt, garlic salt, and pepper in a small bowl; sprinkle all over pork. Heat oil in a large cast-iron skillet or heavy-bottomed pan over high until hot but not smoking. Add pork; cook, turning occasionally, until browned on all sides, about 10 minutes. Transfer pork to a 5- to 6-quart slow cooker. Add beer to skillet; reduce heat to medium, and cook 30 seconds, stirring to scrape up any browned bits from skillet bottom.

Pour beer mixture and reserved 1/2 cup sauce over pork in slow cooker. Cover and cook until pork easily pulls away from bone using a fork, 5 to 6 hours on HIGH or 8 to 10 hours on LOW. Remove pork from slow cooker, and transfer to a large heatproof bowl; let stand 15 minutes. Remove and discard bone. Shred meat using 2 forks. Add 1 cup of the reserved sauce from medium bowl to meat, and toss to coat. Serve pork on buns with remaining sauce on the side.