Would that be correctly called a punt gun? (used for questionable, if not illegal, commercial waterfowl hunting)
It is a wall gun, BUT it certainly would work for punt gunning, though perhaps on the small side ??
At the time they were used, they were not illegal, nor questionable, because at that time one could sell harvested wild game for profit. Punt gunners were not sportsmen, they were professional hunters. Some sources say that up to 50 geese being taken "on the water"..., well the actual technique is to get at a good range, and then fire when they are lifting off the water.... not sitting.
Today, however, using something the size of a punt gun, or even a smaller 4 gauge (1.05 caliber) is not legal for use on waterfowl, the federal limit being 10 gauge [.775] , even if it was a muzzleloader.
Now I do know of a fellow who bought a reproduction swivel gun, which is for folks reading this who might not be familiar, a small artillery piece, swivel mounted, and often found on boats in the 18th century and after.
An example of a swivel gun
The swivel was not bored, but cast solid, so he had it bored out to .770...10 gauge. There is no legal limit to the amount of shot nor powder one uses to hunt waterfowl...so long as the hunter does not exceed 10 gauge AND does not use lead shot. Well this thing would shoot without a problem up to 3 ounces of bismuth, over top of 240 grains of 1Fg.
Was it ever used on geese? He had tested it on cardboard cutouts..., once..., to see what it would do...., so the owner took it out, mounted on a reproduction of an actual punt boat, and did this on the Potomac River..., but I only think he fired it at the end of his day, because he later told me, "I had neglected to remember that the limit at that time was 5 geese, and there was a point system for ducks. So there was always more than five geese that morning OR, when there was four or five geese, there were too many ducks with them." I don't think he would fire at only one or two geese, as the ammo load per shot cost more than $6.00.... and he wouldn't run the risk of taking more than the legal limit, one shot or not, so...,
LD