Punt guns were used in Canada for ducks and geese - back at the turn of the century. Thus, the federal regulations (migratory game bird regulations) today from about WW11 onward(just a guess on the change), restricts use to 10 bore and only shot sized BB and smaller may be carried on the person during water-foul season, with magazine plugs restricting capacity to 2 rnds + THE third can be carried in the chamber.