Unfortunately, you don't give the diameter of your round stock. Scaling bore size to bore size (1.70/5.82), gives a wall thickness of about .275" for the thin part of a M1841 US Coehorn. That would probably be OK as long as it is limited to golf ball shot since little pressure can build up behind a golf ball. Maximum diameter is 2.527". If you have 3" stock, you could scale up but bore undersize to scale, which would give you about 1/2" walls.
