Thank's Ed.
Those measurements will come in handy.
What I'm thinking about now, is a smoothbore 1" gun for use within 25-50 yds. with hardened ball, so if they only work for 1" then that's exactly what I'm looking to do in the future. Not the smaller sizes. Since 'if' I ever start on such a project, (I'm swamped with business right now) it will be a true 1".
I can do the swaging and turning down, so I'll give it a whirl, and keep annealing.
Ever so often I get the blackpowder bug, and if I ever get to this project, maybe I can cure it, especially with 12 drams!!!
I've got a 10-bore Tolley bird gun here that I'm thinking of "scaling up".
But, like I say, thats if I ever get to it, but right now, I'm going to play with making some cases.
Thank's!

p.s.-reason I'm going to use the 20mm cases is because of availability---I could go with RMC, but who knows what will happen down the road?---and 20mm cases will always be found somewhere, because of military use. I'm just thinking 'long term'.
But, RMC stuff is great though, and I'd use them for any other size.