In the days when market hunting was a normal practice, hunters would use pretty huge shotguns to harvest large numbers of waterfowl. These were called punt guns, named after the small shallow-draft boats which they were used on – punts. The largest punt guns had bores of up to 50mm (2 inches) and cannon-type breech mechanisms, and could only be fired from their boat mounts. However, smaller punt guns were also made which could be fired from the shoulder, and this is one of those.
This is a French Darne “Canardière Portatif”, or mobile fowling gun. It is a nominal 4-bore (1 inch) shotgun (although its .920 inch bore actually makes it closer to a 6-bore) with a 1.2m (48 inch) barrel and a rolling block action. It could be fired form the shoulder or mounted to a rope breeching rig on a boat to help absorb recoil. This type was manufactured form 1905 until the 1930s, when market hunting fell out of common practice.