In a large bowl, mix together the ground beef, sour cream, egg, onion soup mix, bread crumbs and pepper using your hands. Form the ground beef into 8 balls, and flatten into patties. Refrigerate for 2 hours so the flavors have a chance to blend.
Preheat a grill for medium heat. Grill the patties for 6 to 8 minutes per side, or until well done.