Abstract: Disclosed herein is a 12-gauge 00 buckshot shotshell having a definitely improved pattern accuracy because of the manner in which the pellets are stacked within the casing prior to firing. The 00 pellets are stacked within a relatively thick-walled casing, or within a relatively thick-walled sleeve within the casing, in single pairs superimposed one upon the other, each pair nesting with its adjacent pair in a common nesting zone and none of the centers of the pellets being disposed within such a nesting zone. The casing must have an effective internal diameter of less than 2.154 times the diameter of the 00 buckshot pellets. The pellets may be stacked so that the two pellets of most of the pairs are slightly axially off-set relative to each other, and so that each pellet is arranged along one of a pair of separate varying helical paths about the axis of the casing.