RJW-

Very nice rifle.
I own and run pinfire double rifles, this is rewarding stuff for sure.
I'd like to see the marks on the barrel flats and the action flats.
That number might not be there to indicate bore dimension.

What is the rifling pattern and rate?
Please get some chamber castings together so we can see your chambers
Rims on rifle and shotguns are typical, they will be smaller than the more modern central fire bore rifle and gun rimmed cartridges. Rimless was specific to the revolvers.

Cheers
Tinker