This is a cut and paste. Total hearsay
A WW2 vet once explained German 9mm ammo to me in the simple terms that all GIs are fond of.
There was a sharp pointed bullet load, brass case, that was to be used in Luger pistols because it was powerful enough to function the Luger action reliably.
The boxes this stuff came in were packed 16 rounds in a box that was marked 'For P-08 Pistol'
There was a rounded bullet, brass case load that was intended for P-38 pistols and all the other 9mm handguns they used, Hi-Powers, Radoms, etc.
Same 16 round boxes only they were marked something like 'Service Load for Pistols.'
There was a rounded bullet load with a blackened case that was for use in submachineguns ONLY, the stuff would break a pistol very quickly with very few shots.
This stuff was packed in boxes of 64 rounds and had German markings that said something like 'Attention, For Submachinegun Use ONLY!'
Late in the war, there was a pointed bullet load with a mild steel or aluminum case that was intended for use in everything 9mm.
This stuff came packed loose in paper wraps of around 500 rounds inside tin lined wooden boxes.
Anyway, that came out of the mouth of someone who was there.