On April 25, 2004, about 1100 Pacific daylight time, an experimental Spirangam Velocity, N216MR, veered off the runway and nosed over while on landing roll at the Boulder City Municipal Airport, Boulder City, Nevada. The owner/builder/pilot was operating the airplane under the provisions of 14 CFR Part 91. The private pilot, the sole occupant, was not injured; the airplane sustained substantial damage. The local area flight departed Boulder City about 0945. Visual meteorological conditions prevailed, and a flight plan had not been filed. In a written report, the pilot stated that after touchdown on runway 33, the nose landing gear started to shimmy. The magnitude of the shimmy amplified as the airplane continued down the runway, and the pilot attempted to correct by applying backpressure to the stick (flight control) to reduce the "load of the nose gear." The pilot said that the nose landing gear came off the runway, and when it touched down again the "shimmy was even worse and the nose was thrown upward." The pilot's forward visibility became impaired by the nose high attitude of the airplane, and the airplane veered off the runway, nosed over, and came to rest inverted. In a telephone interview with a National Transportation Safety Board investigator, the pilot stated that a week prior to the accident the tires were changed. The pilot reported no preimpact mechanical malfunctions or failures with the airplane. A Federal Aviation Administration (FAA) inspector examined the nose landing gear and reported that the castering wheel rotated freely with no binding.