I would guess it was made post WWI and before Sept. 1923 in Suhl. If those script initials are WK, Wilhelm Kelber was the tube knitter. With one Kelber being involved makes one wonder if the inverted K with respect to the Flusststahl krupp essen belongs to Gebrüder Kelber, which began in 1894 and then they split the sheet in 1927. By 1928 Wilhelm Kelber had his own firm and in 1929 Louis Kelber is listed also as having a Gewehrlauffabrik.
If I have the correct Wolf family line, Ernst August Wolf was born in Heinrichs on July 17th, 1853 to Wilhelm & Christine Wolf. He married Friedericke Völker and they had at least 1 son, Karl Wolf who was born on February 1893(expired Nov. 1st, 1971) and he should have attained the rank of master during the latter part of WWI. I would assume it was about this time that he married Gertrud Rosa Werner, so it is most probable that here we have a connection to the Werner gunmaking sourcing line. So that brings us the the tube maker RW or WR. If the owner of Aug. Wolf married a daughter of the Werner gunmaking family, it is possible that the stamp RW is for Robert Werner. It is a common stamp seen post WWI. But in the back of my mind I wonder if Gebrüder Rempt, which used a GR stamp, was rolling their own and if Walter Rempt might have used a WR stamp. Eliminating him from the tubemakers pool would reduce the number of knowns for the equations.
Now there was also a Albert Wilhlem Wolf which hung out his gunmaking shingle in 1908 according to their history page. Not sure just how they were related.
Kind Regards,
Raimey
rse