1 boneless beef rump roast (about 4 pounds)
2 cups barbecue sauce, divided
1 cup root beer
dash of salt and pepper
16 hamburger buns
Place beef in a 3 1/2 to 4 quart slow cooker. Line first with a Reynold's Slow Cooker liner for easy clean up. Mix 1 1/2 cups of barbecue sauce and the root beer in a small mixing bowl and pour over beef. Cover. Cook on low for 10-12 hours. (Can cook on high for 5-6 hours)
About 20 minutes before serving, remove beef from slow-cooker; place in a large bowl. Pour juices into a saucepan and 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 saucepan; pour over shredded beef in slow cooker. Stir in salt and pepper to taste. Spoon about 1/2 cup shredded beef into each bun.