Thanks for the informative input. Some of you guys have really amazing knowledge. Well except for the time travel! If JOe buys it, we can send him back to talk to the Manton brothers.
Back to my gun, based on what has been discussed, I find it hard to comprehend why this "non-standard" cartridge chambering and boring was performed on this gun. Especially when the availabilty of "standard" reamers and boring bars were available. The person who made this gun would have had to supply it with enough cases to be used for some time plus all the other loading paraphernalia. Seems like a lot for a shotgun.
Chris
Chris