1 boneless beef rump roast (4lbs)
2 cups barbecue sauce
1 cup root beer
In a 4 quart slow cooker, place the beef. In a 4 cup measuring cup or bowl mix 1 1/2 cups of the barbecue sauce and root beer; pour over beef.
Cover; cook on low heat setting 10-12 hours.
About 20 minutes before serving, remove beef from the slow cooker; place on large plate. Pour juices from slow cooker into 12 inch skillet. Cook over medium-high heat about 15 minutes, stirring occasionally, until juices are thickened and reduced to about 3 cups. Meanwhile, shred beef with 2 forks; return to slow cooker. Stir remaining 1/2 cup barbecue sauce into reduced juices in skillet; pour over shredded beef in slow cooker. Spoon about 1/2 cup beef mixture into each bun.