Many thanks to Bro. Daryl who alerted me to this Lefaucheux action Imman Meffert In Suhl with Bernard variant barrels. I think this is likely 'end-on' of the thinner 3 iron ribband segment that was folded when butt welded to the thicker breech barrel segment. Steve Culver would know



Looks like the upper 4th lopin segment shown above