Looking over some MG34 barrels I thought it would be interesting to track some of the markings and history.
I'm no expert on codes, so those I couldn't find quickly I noted as "unknown"
bys Ruhrstahl AG, Guss-stahlwerk, Witten
Do (o with umlauts) unknown
716 / RU uknown
Of course, I may be ignorant of which series letters/ numbers is the manufacturer's code. For example, third from left bys 702 awk 40 I take as Ruhrstahl (bys) made in 1940 (40) and I assume 964 is the serial number of the gun. But what is "awk" and "702"?
Let others more learned than I chime in.