On February 16, 2000, about 1600 central standard time, a homebuilt Kitchens Revolution Mini 500B helicopter, N460AK, owned by a private individual impacted with the ground during an autorotation near Hazelhurst, Mississippi. Visual meteorological conditions prevailed at the time, and no flight plan was filed for the 14 CFR Part 91 personal flight. The helicopter was substantially damaged. The private-rated pilot reported serious injuries. The flight had originated from a private helicopter pad at 1530. After flying locally for awhile the pilot attempted a "quick stop" maneuver. He said, after completion of the quick stop he climbed to an altitude of about 400 feet above ground level (agl). He stated that he, "...turned west...[and then] turned towards home...at this point I had descended to about 200 feet agl...flew past the power line right of way and was approaching a large rye grass field and decided to attempt a practice auto rotation down into the field. As I flew over the field I lowered the collective and checked my forward speed at about 60 mph. I then reduced the throttle setting to get the rpm needles to split. I think I was already in trouble when I began the auto rotation from such a low altitude. I am not sure but I also don't think that I had the collective all the way down because after reducing throttle the rotor rpms apparently began to bleed down without my noticing it. I was concentrating my attention outside the helicopter at this time and not paying enough attention to the gauges. At this point things are a little fuzzy as far as my memory is concerned because things started happening pretty fast. At about 50 feet agl I flared...then leveled and started pulling collective. The helicopter started violently shaking...which I now know indicates that the rotors were trying to stall from too low rpms. I knew at this point that I couldn't stop my decent...I don't think I powered back up with the throttle...I hit the ground fairly violently...left landing gear collapsed...the helicopter...roll[ed] onto its left side...and the helicopter finally came to a stop about 30 yards from the point of initial impact." The FAA inspected the wreckage and did not find any mechanical discrepancies. According the FAA's report, "...pilot was performing practice auto rotation. He failed to perform the autorotation correctly and impacted the earth."