Hello there, not sure what you are trying to communicate with your last post Canton.
Have you look at that patent? This prototype was made using this patent.
It was a design dead end I couldn't really worked. It is a Ross handgun. I find it hard to believe that it was found in a German factory though, so I can't see how that could have happened. Never the less, when I looked at the patent, there is an angle that is described between the horizontal plane and the rear of the gun. I looked back at the gun and there is an angle in there, so I am convinced that the gun was made according to those drawings. Now was it actually made by Ross?
I have no idea what the GL and M initials are from, and I should probably post again without any mention of Lugger as it isn't one and unrelated to Georg Luger. But it would be very interesting to know who was working with Ross at the time. I could find very little concerning Ross and printed material is needed to find more answers.
You seem to be a respected member here with high score and loads of posts,find who those initials are from ;-).
Thank you for your comments.