Minimum caliber is 9mm.  Handguns may not be single action at the first shot.  Race-type holsters are not allowed and restrictions on positioning of holsters and magazine pouches exist.  Barrels are limited to 5.5" in length.  Magazines are limited to only 10 rounds after the start signal.  Basic reliability improvements are allowed.  External modifications, other than sights, are not allowed.  After market grips and grip tape are allowed, however, modification to the grips are not allowed.  Common pistols used are Glocks, HKs, Smith & Wesson, Springfield, Sig, and CZs.  Productions is your basic out of the box pistol.   Production scores minor, only.   Production division can be compared to racing "street cars."