I've dabbeled with machining barrels for model cannons, and built several noise makers. I have one tube that I made that has fired cottonballs and newspaper loads for a couple years. I turned the O.D. straight, drilled and reemed the bore to .405 inches, wall thickness is .310 inches. So it is just a noise maker. (Machined from hot rolled round stock) Both the muzzle and breech ends are cut flat with squared corners. I want to make it look like a period cannon by mounting it on some kind of base (either wheeled or sled) that will not require a trunion type mounting. So what am I looking for? At 4 3/4 inches length it's too long to be a mortar.