[bedbugbilly]

I doubt if you are going to find instructions or measured drawings. In essence, the "build" would be like any other "build" of a muzzleloader - but the barrel, stock, etc. are going to be much heavier - which goes without saying.

The best thing would be to do searches and find photos - possibly do a scaled drawing based on the photos and go from there. All that I have seen over the years were of varying gauges and you'[d have to find a barrel maker who could accommodate the dimensions that you decide on as far as barrel gauge, length, etc. and it would be a "custom job.

I owned a 4 gauge "market gun" at one time - probably made in the 1850 era. I would not consider it a "punt gun" though as they were often "mounted" on the boats for shooting in to large numbers of fowl. The gun I owned was a half stock - walnut and was percussion. It was very "heavy duty" - ramrod was iron with large fat button on end to fit the 4 gauge bore. Poured pewter nose cap and iron furniture. Well built but nothing fancy as the job it was built for was to shoot quantities of fowl for the market sales. Barrel was round with just a front bead sight. The gun was built like any other half stock only with large parts, thicker stock, etc. It was also just a single trigger.

I am not aware if thee are any punt guns in museums anywhere - I would imagine there might be but the trick is in finding out where. If you found one close to you, you might be able to make arrangements to take photos and measurements? There might be a photo or two in books on hunting water fowl. I seem to remember seeing a couple of photos of punt guns in just such a book but it was probably 50 years ago at least and I have no idea of the title of the book.

Good luck - sounds like a nice and unique project!