Eric, Now, after checking more carefully,it appears to have a slight taper from the breech to the end of the oct. inlet. From 1.010" to .960", and at the narrowest ,a .7050" waist. I think I might have to go to a 38" colerain barrel as it appears to have a profile just a slight bit bigger then the stock pre-inlet. 42" would be nicer,but who knows. I'll try to get motivated, take and post a picture of it. This stock may make a nice canoe gun!
It has a French "C" type profile yet the lock ,butt plate and trigger plate inlet appear like a Fusil de chasse. It does not have the great humpbacklook to it though. More research will be needed.