15mm cartridge for id please

[Rrickoshae]

Please see the attached photo of a 15mm cartridge that appears German but the headstamp is unusual. The case is a standard 96mm and is undated.
the headstamp reads 51 auj waffen stamp. The stamping is fairly faint and the 51 could possibly be 5.i
I am not familiar with the manufacturers code and it’s odd that it has no date unless the 51 is the date.

any thoughts please? Many thanks, Dave

 

[ThomasP]

If I am reading the manufacturer's code correctly (auj) then I have it listed (in my notes) as

Monheimer Ketten- u. Metallwaren-lndustrie Poetz u. Sand, Monheim-Duesseldorf

NOTE that the spelling & name have changed over the years, and today it is usually listed as

Monheimer Ketten- und Metallwarenindustrie Potz & Sand GmbH & Co, Monheim am Rhein

 

[Rrickoshae]

that’s excellent Thom, thank you. Any thoughts why no date stamp?

atb Dave