The powder chamber is machined out of 5 /12" by 5 1/2 round stock with a 2x2" powder chamber.
This was made at a large machine shop. The same machine shop also took the O2 tanks and put them on the lathe and trued up the inner bore to the correct windage. They also did the welding of the chamber to te tanks. They have the right tools to do the job correct. The rest of it was done buy another welder who did the trunions for latter use on a carriage but also did the ball mount, base plate and legs. Did a real good job. Did a test fire before he finishish all up and paint. Did a very nice job. I will get pics when I get it set up and fire it.
Here's another cool fact. After I commisioned the Cannon/Morter I stated looking for balls. Got lucky and found a local alley tat was closed. The guy sold the cannon maker and I all the balls and pins for a heck of a deal. Boy do we have balls.