The pilot reported that he was tasked with ferrying the homebuilt airplane to its new owner. Having no prior time in the airplane, he flew it around the pattern to familiarize himself with the airplane's controls. The pilot stated that since he was not sure what the fuel burn of the airplane was he made an estimate using a similar aircraft with the same engine. After refueling the airplane to its 24 gallon maximum capacity, the pilot took off for the cross country to the destination airport. En route he climbed the airplane up to 9,500 feet, leaned the mixture, and set the engine RPM to 2500. He estimated that the engine was using 4 to 4 1/2 gallons per hour, which by his calculations would give him 5 hours of flight time at that altitude. After 3.8 hours of flight, the pilot noticed the fuel gauge read 1/4th of a tank. About 6 minutes later, the engine quit and the pilot was forced to initiate an off airport forced landing. During the landing attempt, the pilot hit a fence which caused the airplane to impact the ground with its left wing and tumble. The airplane suffered substantial damage to both wings and part of the fuselage. The pilot stated that the fuel gauge acted normally during flight, but remained between 1/8th to 1/4th of a tank even after the airplane ran out of gas. An inspection of the fuel gauge by an A&P mechanic showed that the gauge was functional; however, the mechanic described the type of fuel gauge as typically being difficult to calibrate and that they tend to only read accurately when the tank is full. Examination of the airplane's fuel tanks showed they were empty and the fuel system was intact.