On February 21, 1996, at 1900 mountain standard time, a Beech 35, N3363V, registered to and operated by the pilot as a 14 CFR 91 personal flight, landed with the landing gear retracted at Laurel, Montana. Visual meteorological conditions prevailed at the time and no flight plan was filed. The airplane was substantially damaged and the private pilot and his passenger were not injured. The flight originated from Columbus, Montana, about one half hour before the accident. The pilot reported that he was returning to Laurel after washing his airplane. The pilot stated that he entered the traffic pattern for runway 22 and began his "GUMP" preparations while making announcements of his position in the pattern. The pilot stated that he did not visually check to make sure that the landing gear was extended, as there was no light that showed the mechanical position of the landing gear. The pilot also stated that the red landing gear panel light was out and the warning horn did not sound. The airplane touched down with the landing gear unintentionally retracted. After the accident, the pilot had the airplane drug approximately 20 feet to clear the runway. Later, the airplane was raised and the landing gear was extended. The airplane was then towed to the parking area. The pilot claims that the structural damage to the bulkhead was done when the airplane was drug off the runway. The Federal Aviation Administration inspector from the Helena, Montana, Flight Standards District Office and two FAA certificated mechanics reported that the bulkhead was ground down and the material was thin. The FAA inspector and one mechanic felt that the extensive grinding was a result of the gear up landing. The second mechanic did not have an opinion.