We shoot quite a few Canadas each year here in the US. We factor two things in making our cartridge selection. First, is time of season. During our early season (September ) when the geese have not fully feathered up, lighter loads (# 3 or even 4 will work at closer ranges (30 yards and in). During late season, the geese will have a much thicker feathering and therefore we prefer #2 or bbs in steel, or switch to Hevi or some other high density shot.