2 pounds ground beef
1 (12-ounce) can tomato paste
1 3/4 cups catsup
1/4 cup minced onion
3 tablespoons sweet relish
2 tablespoons chopped celery
2 tablespoons brown sugar
3/4 teaspoon garlic powder
1/4 teaspoon chili powder
1/4 green bell pepper, chopped
14 (4-inch round) buns, split