Just inherited this from my father, who got it from his father from Germany during WWII. Spent about 2 hours cleaning and getting everything functional. Put 50 rounds through it (shoots low and left) and decided I wanted to learn more about it. I posted it on the Luger forum and was overwhelmed with helpful/ knowledge people. I ended up being able to verify that it is a 1941 Mauser byf "Early Black Widow" Luger. I was able to match every marking minus the Locking Bolt Takedown Lever, which is a replica or from another gun in that era. I'm on the hunt to find a #10 stamped takedown lever to make it 100% complete but I thought some other may enjoy looking at it. It is dirty in the pictures as I just got back from the range when I decided to post it to learn more.