See my answer in "ask the Gun Writers" as with most guns just about any part can be made or repaired most of us shooting older combos and drillings are in the same boat pretty hard to find parts for a prewar German drilling. I shoot Bernardelli and BRNO combo guns and several drillings. Every once in awhile you see FEG O/U shotguns for sale.
A 12ga in a combo gun handles pretty nice, when you get a 12ga in a drilling it can feel pretty much like a club. My BRNO has a set of 12ga skeet barrels with it and feels very good on the skeet/SC range although a bit heavy to hike the prairies with.
