But my question is the slide does not lock back even with the magazine inserted.
That is certainly odd since AFAIK the letter prefix was continued right up to the end of production at Znaim. The only other four digit no letter guns were the early Polish production, and the first production under the Germans when they started numbering over. The first Z series went to the second A series with no "letterless" numbers between.
But yours has the Znaim wood groved grips, no slot, no takedown lever, probably the large screws without bushings, called Type IIIa by some writers if the bnz pistols are Type IV. (The typing is not consistent and not rigid since changes were phased in and flowed into another with no absolute cutoffs.)
One thing that would help would be a good picture of the serial number. If you want, put a piece of gummed paper over the last number.
By some standards, those are the latest, crudest and least desireable of the Radoms, but some collectors will pay high dollar for the late guns, especially the bnz guns as they are uncommon.
Jim
My type 4 Radom has a slide lock issue too.
If hand-racking the slide, it locks back with a mag in.
If the mag is ejected, it will unlock the slide.
If no mag is in and the slide manually locked back, it will self-unlock after a half second or so.
When shooting, it won't lock back on empty 70% of the time as apparently the recoil is severe enough that it overcomes the follower spring.
I came to the conclusion that the slide catch slot wasn't cut square enough (like kman).
Guys: I have read all your "posts" on having problems locking back your pistols (radom) slide. On the late produced Radoms the slide is locked back by lifting up on the hammer drop lever while holding the slide back, thus the slide will lock on a notch cut on the hammer. To drop the slide, just depress the hammer drop lever. I hope this helps. I have owned a lot of radoms in my life (I'm 67 years old) they are a great firearm!! I have heard that toward the end of production (Jan thru April 45) some radoms were produced without even the hammer drop lever, I have never seen one, though I would like to as it must be impossible to hold back the slide. By the way the only real "weakness" in the radom is on the end of the recoil rod. I have bought more than a few of them thru the years where they were either broken off or wore off.
Regards
Dakotaern