Information I have read on the Merkel Brothers (Much of it from GGCA magazines, I am sure you have them as well, and supported from other sources such as this site and other internet sites) indicates that fairly early on, the Brothers developed differences of opinion, shall we say, and that both Oscar and Bernard split off and founded their own firms. Both of them, however, seemingly maintained some business relationships at least with the Gebruder Merkel firm, as it seems clear that both obtained parts from GM. I have never seen a side by side Oscar Merkel (may be some, I just have not seen them) nor have I seen an O/U Bernard Merkel (again, may be some, but I have not seen one.) The actions used by both Oscar and Bernard appear so nearly identical to the O/U and the S x S actions used by GM that logic would indicate they purchased actions from the larger GM firm. It's clear, in the case of the two BeMeSu guns I had, that Berhard also obtained forend irons already stamped with the GM shield from the larger firm. Both my side by side BeMeSu guns were 16 gauge, both were scalloped back boxlock actions, and both were finished to a "middle" grade with some decent engraving (game scenes on both) and wood with some figure in it, not just plain wood. The Oscar Merkel O/U guns I have seen were all finished as upper grade guns, with VERY good finish details.
I happened to think of another similarity to the BeMeSu stamp that I am quite sure is Bernard Merkel, Suhl: In addition to the GM in a shield stamp often used by Gebruder Merkel, I am sure you have seen "Geme" sometimes stamped on Gebruder Merkel guns. Again, it's nothing but the first two letters of Gebruder Merkel, just as in BeMeSu. To me, that seems just a further point of evidence.
I am going to try and dig out, from old catalogs that I have, photos of the early gun factories and try and post them. The Simson factory was absolutely enormous, and was said in GGCA publications to be the largest in pre war Europe, not just Germany. That would include being larger than the very large FN facilitis at Leige. J P Sauer also had very large facilities, though smaller than Simson. Gebruder Merkel was a large facility also, but I seem to remember them being somewhere smaller in size than Sauer. Other German makers had FAR smaller gun works, most or at least many being cottage industries, like the photo of the Bernard Merkel works. Comparison of those old photos should be interesting, I'll try to get that done soon.
It's the sheer size of the Simson, Sauer, and Merkel factories that cause me to wonder why in the world they would outsource the manufacture of any parts at all. I believe it will be found to be the opposite, that the large factories forged the various action designs and made the barrels and most parts, and sold forgings and semi finished parts or even completed guns to the smaller "makers", who then finished, embellished them, and in many cases laid claim to "making" them. I know there were other tube makers other than the "Big Three", and that all 3 used Krupp barrels as well as their own, but I believe these 3 firms accounted for at least nearly all the actions. We can't forget the Belgian work force, they supplied parts to German makers as well, apparently.
Still lots of archive digging needed to unravel all the German gun making mysteries.
