Gary,
....Are you aware of the 1/3 bore size to O.D. of the tube by the breach ?....
I am now. These were built several years ago when I needed a break from my' normal winter 'build hobby, steam engines. I just used what looked right. Been wrong before. LOL Summer hobby is old British cars. The BP cannon's have never been fired other than caps. Think it's safe to shoot BP?
Every time I get the urge to make noise, I go for a BIG cannon I made. Cast iron with a steel liner somewhere around 80 cal. around 40 lbs with the steel carriage. Here's some more pics of others. None of the big one handy. Let me know when you've seen enough. LOL
I call myself a 'hobbyist' and drive my wife nut displaying my models around the house. Cannons, engines, cement mixers, turbines, ships, guns........I could go on.