On January 8, 2015, about 1640 central standard time, a Cessna 210B airplane, N9565X, was substantially damaged when the main landing gear collapsed at the Sullivan Regional Airport (KUUV), Sullivan, Missouri. The private pilot was not injured. The personal flight was conducted under the provisions of 14 Code of Federal Regulations Part 91 without a flight plan. The flight departed Jefferson City Memorial Airport (KJEF), Jefferson City, Missouri, about 1600, and was en route to KUUV. According to the pilot, after takeoff he did not receive the cockpit annunciation indicating that the landing gear was retracted. The air traffic controller confirmed that the landing gear was not completely retracted. The pilot cycled the landing gear and utilized the hand pump; however he was unsuccessful in extending or retracting the landing gear. The pilot elected to fly to KUUV, his home airport, to land. His mechanic communicated with him and stated that it appeared that his nose landing gear was down so he elected to land on the runway. During the landing, the nose landing gear remained extended; however, the main landing gear collapsed. The spar on the right horizontal stabilizer was bent and the right wing skin, wing tip, and outer spar were bent. An examination of the landing gear system revealed that the right landing gear actuator (part number 1280501-2) was cracked and had leaked hydraulic fluid. An examination of the remaining system revealed no anomalies. The actuator was retained and shipped to a laboratory for further examination. The results of that examination revealed that the cylinder of the actuator cracked longitudinally and transversely. The crack initiated at the snap ring groove located at the end of the cylinder. The crack at the snap ring revealed signatures consistent with fatigue cracking. The crack which extended the length of the cylinder revealed signatures consistent with ductile overload. Details to the results of this examination are available in the docket to this report. The most recent annual inspection was conducted on October 22, 2013. There was no recent maintenance conducted on the landing gear.