Swiss Gunsmith Acceptance Mark

[Steve D]

Luger Forum - Could a Swiss collector help with a question for a first time poster? I have a 1906/1920 (?) re-work for which I have not been able to identify the gunsmith mark. The pistol is a very early commercial serial number built on the long frame. Re-worked in Switzerland, it has a new barrel and I believe new receiver (marked internally only with a "G", which indicates it was manufactured in 1912 (?). Close examination of the barrel/receiver index mark indicates that no other barrel had been mated to the receiver. I suspect it also got new grips as they have no internal numbers. The barrel is serialed to the frame and Crown-N proofed, with the "lazy" Crown-N proof stamped also on the left side of the receiver.

My question centers on the Swiss gunsmith acceptance mark. It is identical to the well-known Fluckiger mark, but instead of the "FZ" initials, this mark has the initials "RB". The mark was also stamped on the bottom of the magazine, and filled with some sort of paint.

Was the enrayed Federal Cross a standard Swiss mark for which any gunsmith added his particular initials? Also, do the Crown-N proofs indicate that the gun was returned to Germany for proofing? Why would it not have been submitted for Swiss proofing which would have satisfied that countries requirements? And then, why is the receiver proof sideways? Shouldn't it have been vertical by this date? Lastly, is there a definitive was to identify the barrel as manufactured by Hammerli rather than a Swiss military piece?

Thanks in advance.