7.92mm headstamp query

The attached picture shows a German 7.92mm headstamp. It is 4 15 S z D. , the ‘z’ is new to me, can anyone tell me what it means. Thanks in advance


I believe the “z” stands for Zink, german for “zinc,” and indicates the new brass alloy with increased zinc and reduced copper content. This was later indicated by the notation “S67.” Jack


The Germans use for the S cartridge cases English sink that was of high quality.
In the middle of the war the English sink began to ran out , therefore the Germans began produce
cartridge cases with German sink.
The ammunition plant of Dresden ( and only )used the Z in the headstamp to indicate this. Only for a few months.


Thanks Jack and Leon