On March 21, 2004, at approximately 1200 mountain standard time, a Cessna T310R, N3465G, was substantially damaged during a gear-up landing at Jefferson County Airport (BLC), Broomfield, Colorado. The private pilot, the sole occupant on board, was not injured. Visual meteorological conditions prevailed. A visual flight rules flight plan had been filed for the flight being conducted under the provisions of Title 14 CFR Part 91. The cross-country flight had departed Granby, Colorado, at approximately 1100. According to the pilot, he had been experiencing electrical problems for the majority of his flight. Upon arriving at BJC, he was unable to communicate with the tower and entered a traffic pattern for runway 29R and began to look for light gun signals. He stated that he had extended the flaps to 15 degrees and verified via a checklist that the gear was down. When he turned final, he noticed an airplane on the runway and initiated a go-around. The pilot said that he entered a downwind for runway 29R for a second time, "lowered his landing gear and set 15 [degrees] flaps." The pilot "noticed that the flap indicator was not down," so he raised the flaps lever to avoid problems later. The pilot did not visually verify that his gear was down. During the landing flare, both propellers came in contact with the runway and the airplane slid along the runway for several hundred feet, substantially damaging a bulkhead.