A stripped receiver made by Berlin-Lubecker  The original letter code for them was duv but

that was changed late war to qve.   This one was obviously rejected because of at least one crack.

The interesting thing is that they stamped a "U" over the crack and over the waffenamt stamp.  The

"U" has uses in relation to P.38s so I wonder if there is some connection or if this is just a coincidence.