Strange Marking or Proof On Bundeswehr Reused Wartime MG42’s

[Joe Mc]

Hi all,

I’ve noticed on some MG42’s reissued by the Bundeswehr (Wartime Made converted to 7.62 NOT scratch built post war types) that there is an unusual proof stamp near the wartime markings and I can’t find anything anywhere what it’s for. Does anyone know what it is please?

Any help would be very much appreciated!

Thank you,

Joe