[Ron Wood]

Pete,
I would opt for "odd factory hybrid" that may or may not have been made up for presentation or shooting award. The frame and rear toggle link are of the 1900 configuration (that is an assumption on the frame since it would need the toggle latch). The receiver may or may not be 1900. It could be 1906 long frame, but I am guessing it too is 1900 since it matches up so well with the 1900 rear togggle link. The overall length of a 1900 forward toggle link and breech block is the same as the 1906 and 1929, so they could be interchanged/swapped out. The barrel is probably a Swiss replacement since it has the Bernerprobe proof. A 1900 barrel would have been made by DWM.

The receiver looks like it goes with the 1906 breech block, but a 1900 receiver can be modified to look just like this one. The top rear of the chamber of a 1900 receiver would have to have that little cross chamfer and extractor cut made, but that is quite easy to do, particularly if the barrel is removed.

I think that the guys at Waffenfabrik Bern were feeling frisky and made up a couple of these out of parts on hand just to create an "improvement" on the 1900 and jazz it up a bit for some big wig or special order.