to win the open HOA in a major shoot, depending on the weather (though a perfect score of 400 remains a rare and noteworthy event). For example, the HOA title at the 2007 US Open tournament, shot in Albuquerque, New Mexico between September 6 and 9, was won in a shoot off between two competitors, each of whom shot a combined score of 399 out of a possible 400. Recognizing that a high level of perfection is beyond the skill, interest, or time available to most shooters, NSSA competitions are subdivided into several classes, each based on the running average score shot over the last five most recent events shot in each gauge, prior to any given competition. This permits shooters of roughly equal ability at the relevant point in time to compete against each other for the individual and HOA titles in their class. Other national versions of skeet (e.g., English skeet) typically make similar changes to the rules to make them easier. See also ISSF Olympic skeet ISSF shooting events Trap shooting Double trap International Shooting Sport Federation U.S. intercollegiate trap and skeet shooting champions References National associations National Skeet Shooting Association (US) Clay Pigeon Shooting Association (UK) New Zealand Clay Target Association Australian Clay Target Association US state associations North Carolina Skeet Shooting Association (US) Mississippi Skeet Shooting Association (US) New Jersey Skeet Shooting Association (US) US zone associations Zone VI Skeet Shooting Association (AR, LA, MS, OK, TX) (US) External links Skeet, trap, and sporting clay club locator (U.S.) ISSF shooting events Shotgun shooting sports Rifle and pistol shooting sports Clay pigeon shooting fr:Ball-trap