The other thing I am not familiar with, is posting etiquette. Am I out of line by doubling-up or do you want more images?
The bore is 2 1/2" but I since the tube is layered similarly to an original, I do not load it as a muzzle loader would be loaded. I gauge the powder charge to fit the breechblock measurements, i.e. the recess width is 1 3/4", depth 3 7/8" and of paramount importance, the 7/8" wall. Remember, this is not a muzzle-loader.
Originals often began with a mandrel wrapped with a sheet of iron that would have sported a welded seam. It was then wrapped with welded iron bars. As a variation, the wooden mandrel was only wrapped in iron bars.
I began with a seamed tube, which was then wrapped with some welded re-bars.
Now once again I exercised one of the variations. An original had 2 main choices, e.g. wrapping the welded bars in a sheet of iron (rare) and then hoop it or just hoop it (common). I sleeved my iron bars with a seamless tube and then hooped it. Mine imitates the rare variation.
My problem is with the American Artillery Association guidelines in that I do not fit. They call for a seamless "liner" and my has a seamless "outer". Unlike belly buttons where inner and outer are equal in function, the cannon barrel is debateable. Moot point as far as I am personally concerned.
More to come if you are interested?