Thank you very much for your answer. Here are some additional photos: The Action: [Linked Image from i.postimg.cc], barrel set from Andreas August Ahl Bonn am Rhein: [Linked Image from i.postimg.cc], [Linked Image from i.postimg.cc] and barrel set from Eduard Kettner: [Linked Image from i.postimg.cc] .Sorry for the quality of the photos, I didn't have much time. Do you think the numbers 131, 239, 491 are proof dates? This drilling seems older than 1931...