Hi Hammer1,
Even if there is no real standard method of measuring the pattern of shotgun shell the european manufacturers use a target with circles of different diameters. They place the target at 37m around 40 yards and count the number of pellets that strike in the 76cm (30inches) circle then look for the "empties" and how the pellet are spread in the circle. Today they use electronic system as the US makers do. They shoot targets with each different choke tubes. You can adapt this method to the shotgun and shell you use and to the game you hunt.
In France, Germany, Italy, Spain etc... we produce speciality loads for woodcock hunting, made to open very fast, for use in heavy bushes. Most of time, we pattern them from 8m (9yards) to 18m (20 yards) which correspond to the max distances most of woodcocks are shooted at in our forest. This cartridges are also use for rabbit hunting with dogs in bushes and dense vegetation where shots are close.
Hope it can help you.
Dom
