On August 14, 2005, about 0740 Pacific daylight time, an experimental Barnes Lancair Legacy, N508DB, experienced a total loss of engine power during cruise flight and the pilot made a forced landing in an open field about 6 miles west of the Pine Mountain Lake (uncontrolled) Airport, Groveland, California. The pilot elected to land with the landing gear retracted. The airplane was substantially damaged as it slid to a stop and impacted a fence. The private pilot was not injured. Visual meteorological conditions prevailed, and no flight plan had been filed. The personal flight was performed under the provisions of 14 CFR Part 91, and it originated from San Jose, California, about 0715. The pilot reported to the National Transportation Safety Board investigator that he believed he had taken off with 18 gallons of fuel on board as indicated by the fuel gauges. He estimated that the required fuel for his planned flight was between 8 and 9 gallons, but he had experienced fuel exhaustion while en route. He subsequently reported that upon his examination of the airplane he noted the fuel sensors were improperly calibrated. The pilot reported that he did not experience any malfunction or failure with his airplane.