shotgun barrel length
Semi-automatic shotguns with a barrel length of less than 469.9 mm (18.50 in) are considered restricted and any shotgun that has been altered so its barrel length is less than 457 mm (18.0 in) or if its overall length is less than 660 mm (26 in) is considered prohibited. backpacker shotgun has a short barrel and either a full-size stock or pistol grip, depending on legislation in intended markets. The overall length of these weapons is frequently less than 90 cm (35 in), with some measuring up at less than 63 cm (25 in).