I have examples of Sauer, Merkel, Simson, (including guns marked Simson, BSW, and Gustloff Werke), Meffert, Griefelt, Emil Nordheim, Haenel, Max Fischer, R. W. S., and Heym all with Krupp barrels marked variously either simply Krupp Essen, Spezial Gewehr Laufstahl, or with a 3 ring Krupp logo or a 4 ring Krupp logo. I have not seen Bochumer Verein nor Rheinmetall barrels on any of my guns. Even the R. W. S. 16 hammer gun is with Krupp barrels, although I recall Raimey mentioning in the past some connection of R. W. S. with Rheinmettal from his research.
I have seen many different types of Krupp, and have seen unmarked German barrels of the period, but not the others. I would assume they were far smaller maker than Krupp, accounting for the far fewer examples.
Good luck, Raimey, with your research. Hope you can nail it down. If you do, a book is in order.
