Cartridges
Shotgun cartridges are readily available in gun shops and at shooting grounds, and within limitations as to the shot size and the weight of the shot load are suitable for clay shooting at CPSA affiliated grounds and for use in events coming under CPSA rules. Though home loaded cartridges allow the user to customize the ballistic characteristics of their shells, they are generally not allowed at clay pigeon shooting events unless specified otherwise.
Care should be taken that cartridges to be used are compatible with the shotgun that is going to fire them. The instructions and specifications are printed on the boxes. For clay competition, shot size must not exceed 2.6 mm/English No. 6. The shot load must be a maximum 28 g (0.99 oz) for all domestic disciplines; or 24 g (0.85 oz) for Olympic trap, Olympic skeet, and double trap; up to 28 g for FITASC sporting (from 2005); and 36 g (1.3 oz) for helice.
Read more about this topic: Clay Pigeon Shooting