It actually looks like a F.W. Keler Modell Nr. 104/105. Are there any monograms between the strikers on the standing breech or on the left side of the aft lug? the 40k serial number would have to originated at an established firm & I don't know that Rheinmetall would have turned out that many by WWI. Not sure on Keler but I'll look. So it is devoid of a Nitro stamp? On the right flat is what looks to be the initials JCM or is that wear from the water table? If on both, the he is pretty much our culprit.
Kind Regards,
Raimey
rse
