German sub-machine gun ammo

Orv, I have several boxes of WWII (1942 I think) German 9mm that is marked "Nur fur MP" which means of course "only for machine pistol". I don't really know first hand if this is too "hot" for Lugers/P38 and your comment about universal use makes a lot of sense. I can only guess that due to the relativly small amount of pistol ammo that a soldier would expend (compared to a machine pistol bearer) there was an attempt to provide non-MP (hot loads)for pistols, but in a pinch the MP 9mm would work.