DmColonial, thanks so much for the word on the gauge. As I near the end of a complete disassembly and cleaning, I was able to take an accurate measurement of the barrels and they are indeed 11ga.
Hope to post some final pictures as well as a couple of interesting “finds” as a result of the thorough cleaning.
I take it you didn't find a loaded charge in either bore during cleaning? I just acquired a double barrel muzzleloader last week. Low and behold the right barrel had a charge of what looked like #7 shot in it. Ya never know and can never be too safe!!