Hi Gunder,
I have a GL Rasch from Braunschweig, that is a Collath action. I have been told that GL Rasch was a retailer and not an actual maker. My 16ga Rasch is very well made and my first side by side given to me by my dad, he recieved it from a Mr Wurtz who brought it from Germany when he emigrated to the US in the 1920's.
Sorry I don't have more information for you maybe some of the more knowledgable will ad some.



Jeff G.