On March 13, 1999, at 1315 hours Pacific standard time, a Cessna 305A, N5188G, owned and operated by the pilot, ground looped and impacted terrain during landing rollout at the uncontrolled Harris Ranch Airport, Coalinga, California. The airplane was substantially damaged, and the private pilot was not injured. Visual meteorological conditions prevailed during the personal flight conducted under 14 CFR Part 91, and no flight plan was filed. The flight originated from Tracy, California, about 1200. The pilot reported that he had recently purchased the conventional gear airplane, and he was familiar with its operation and flight characteristics. No mechanical malfunctions were experienced with the airplane during landing rollout on runway 32. Several airplanes had landed ahead of him without experiencing apparent difficulty. In the pilot's completed report, he indicated that the local surface wind was from about 090 degrees, between 3 and 5 knots. The pilot reported that he tried to perform a wheel landing, but the airplane swerved. He then lost directional control and ground looped.