You're thinking of the US Springfield 1903. It used a Mauser style bolt-action that was protected by a patent. Mausesr sued and won. The US gov had to pay license fees for it. I think actual payment was delayed until after the war was over.
It went far father than firearms, later - in WWII you had a shared military-industrial-complex supplying both sides, with entities like GM and Ford supplying huge quantities of armaments to both sides - Ford went so far as to enslave most of the population of Rostov-na-Donu.
I wonder if at some point there will be unified suppliers and supply chains for all armaments for all actors, acting entirely independently of any nation state. Corporations are more or less there in terms of their ability to hop jurisdictions and work around international law.
In fact, maybe we do already have this, but it’s non-obvious.
It's worth remembering that international subsidiaries inside Germany were entirely cut off from their parent companies. There were no executives from the parent corporation present in Germany, all the other employees were Germans, no money could be transferred out of Germany, and after a while they even had to get special permission to send telegrams in or out. They still called themselves Ford Germany or IBM Germany or whatever, but the reality is that this was just a name that they used; there were no real ties of ownership or control left. Naturally when France fell, the French subsidies suffered the same fate, or even worse.
ITT was another conglomerate that got fat selling to both the Allies and the Axis; radar sets made by ITT subsidiary Federal Telephone and Radio were used to shoot down planes built by ITT subsidiary Focke-Wulf (partially owned by radio manufacturer and ITT subsidiary Lorenz).
Well it's unlikely that has complete control over the supply chain and so it's corporations doing business with each other. They'll find a rapidly decreasing number of people willing to do business if they ride roughshod over others IP.
