You can reverse that question as well - why would Geco, if they owned the Sinoxid name, allow
RWS to so prominently display it on all their produce catalogs, not only in text, but in huge letters on the covers. It is on all of the catalogs from the 1930s, and even appears in the text of the “RWS Mitteilungen Nr. 4, Jahreswene 1953/54,” certainly one of the earliest post-war RWS publications? First, despite the claim, I personally doubt that GECO was the sole owner of the right to use that name. That is my own opinion pretty much etched in stone. The use by both companies of the Trademark name for RWS-made primers (see below) was likely part of the 1927 agreement. Even if it is correct that GECO owned the trademark, for whatever reasons seems beyond logic, likely would have given their “partner” under the 1927 agreement permission to use it. If this had not occurred I have no doubt that after GECO saw the prominent and wide use of the term on their catalogs and other advertising material, a lawsuit would have followed.
Regarding GECO manufacture of primers, I am satisfied that items on this thread have documented that they did not make primers after 1928. A search of all my 16-round 9 mm boxes of Geco (dnh) manufacture, not as many as some collectors have, but still between 10 and 20, yielded none where Geco was the primer supplier. They were supplied by several companies, and RWS was one of them. In fact, RWS shows up on a very good percentage as the primer supplier on many of my boxes. They even used the plain initials RWS on some, and then the “dnf” code.
So, (1) I see no evidence that Geco even primers in the 1930s and 1940s; (2) RWS did make primers and were one of the suppliers of them to Geco. I cannot say that Geco did not make a single primer after 1928, although I am satisfied with the explanation of such on this thread, but if they did, they were likely for something other than small arms ammunition.
If anyone does have a 16-round box where GECO (dnh) is the loading factory, and the primers are shown as made by dnf (RWS) I would like to get a picture of it for my files. It would be very important to this discussion.
And yes, I agree 100% that agreements, and other interactions between corporations, certainly not limited to those between RWS and Geco, are often very, very complicated, sometimes simply because of various legitimate factors, and sometimes made that way for nefarious purposes.
Note: Edited to remove the “not” from “a lawsuit would have followed.” My thought is that Geco, under the circumstances discussed in that passage, WOULD have sued other companies. The word “not” was a confusion in typing, on my part.