1. Preheat your grill to medium-high heat.
2. Cut the tops and bottoms off the onions, peel them, and cut a small hole in the top of each onion, removing the core.
3. In a bowl, mix together the ground beef, breadcrumbs, bacon, cheddar cheese, jalapenos, barbecue sauce, salt, and pepper.
4. Stuff each onion with the beef mixture, packing it tightly.
5. Wrap each stuffed onion in aluminum foil, making sure they are fully sealed.
6. Place the foil-wrapped onion bombs on the grill and cook for about 45 minutes, turning occasionally, until the onions are soft and the beef is cooked through.
7. Carefully unwrap the onion bombs and place them back on the grill to char the outside slightly.
8. Remove from the grill and let cool before serving. Enjoy your firecracker bacon cheddar cheeseburger stuffed onion bombs!