The book "Outlaw Gunner" by Harry Walsh ... a former US F&WS Warden gives a very good account of a lot of the old market gunners weaponry and gear. Loads of info within the book concerning layout boats, battery's, punt & multi-barrel battery guns, lights, live decoys, etc. etc.
In addition, James M. Michener did a fair bit of research on market gunning
as one of the components in his novel "Chesapeake". Beyond the history lesson we all get with a Michener read, there is some stuff mid-book about the baymen, ducks, geese, other wildlife & gunning on the Chesapeake that every waterfowler should read. Just how one of the "scofflaws" kept the Warden from finding the big "Twombly" punt gun was quite ingenious. I won't spoil it for you.
Sworn to secrecy, I know where there is a fully- operational genuine punt
gun which was manufatured in England. Provenance with the gun lists it's
load data ... don't tremember the charge of black powder, but do recall,
" 1lb. of Swan Shot" as being the payload.
This "gun" is a very well-made cap lock with an external hammer, that looks to strike a big percussion cap - like a musket cap. The "stock" is rather short and has a flat bottom, obviously meant to sit on the floor of the duck punt, and it has hardware meant to rope it into place to help absorb recoil. While I haven't measured it, the barrel looks to be about 7 feet long, and has a diameter I would guess to be about 2 inches. Weight - maybe 40 lbs.
Would I like to touch it off some night over the marshes of Lake Erie ... you betcha ! Probably hasn't been done for almost
a 100 years ! Well ... then again, maybe 50 or 60 !