Today a difficult question !!
I have been researching the topic of German MG 08 and 08/15 belt makers for many years. So far I have been unable to identify one of the most important WW1 maker, namely the one coded RK or a logo with the “R” mirrored sticked to the “K”.
[color=blue]RK logo on MG 08 starter.[/color]
RK logo in circle on 1917-dated MG 08/15 belt
RK with standard letters on 1917-dated MG08/15 belt
This maker appeared end of 1914 on MG 08 belts and has been observed until at least 1917 on MG08/15 belts.
The same maker manufactured export belts in 1915-16 for Bulgaria for their Maxims in 8x50R.
Finally, still the same maker manufactured non-standard belts for maxims fitted with specific spacers in 1915 ; these belts bear the German marking “DRGM” which corresponds to “Deutsches Gebrauchsmuster”= “German Registered Design”. You will note that it is not a Patent but only a Registered Design. Looking through the various German Patents on belts did not allow to find any company with a name which could fit with the letters R and K. So far I have been unable to locate any source for German WW1 Registered Designs (DRGM).
Now this forum is my last chance to clarify this issue… otherwise my study on German MG08 and 08/15 belts will still contain the “RK” entry as “unidentified”.
Thank you all in advance for any hint,