In a large bowl, combine ground beef, bread crumbs, onion, milk, egg, salt, Worcestershire sauce, and ground black pepper.
Mix together, and shape into meatballs.
In a large skillet, heat shortening over medium heat.
Add meatballs, and cook until browned, about 5 to 7 minutes.
Remove from skillet, and drain on paper towels.
Add chili sauce and jelly to skillet; heat, stirring, until jelly is melted. Return meatballs to skillet, and stir until coated. Reduce heat to low. Simmer, uncovered, for 30 minutes.