The solo private pilot said he made a straight-in approach to land, but was too high and fast, and did a go-around. He reported that on the next landing approach, he felt that he got behind the airplane, and again approached too high and fast, but landed anyway. He said the airplane ran off the end of the runway, and into a barrier. The pilot reported that there were no mechanical anomalies with the airplane prior to the accident. He said the airplane received damage to the nose and windshield. An FAA air safety inspector, who visited the airport, said he spoke with a witness who saw both approaches. He said the witness told him that on both approaches the airplane was high and fast, and that on the second approach the pilot forced the airplane onto the runway abruptly, running off the end and into a barrier.