How to date a mismatch MP40?

[Lewisfan]

The receiver and all attached parts are matching.  The lower parts are all matching. Upper and lower don't match.  

The lower is a bnz 41 date.  The upper has the SN (4-digit starting with "8") followed with an "e".  The only WaA I see are WaA623. Barrel nut is 6-sided and the receiver has a safety "hang the bolt" slot.  Magwell is ribbed.

Is this enough info to verify a manufacturing date?  I assume, based on the WaA that this is a Steyr gun. I'm just curious to find out what year it was made.

[Rekraps]

Pics?

[Rekraps]

Since its the upper receiver that determines the SN for registration purposes, then the SN just forward of the magazine well should be the one on the registration, BUT, the mfg date is on the end cap of the lower receiver, so I'd use that bnz41 as the mfg date on the forms.

I'd love to have an ATF person comment on this. 

[MS Collector]

Here is my bnz41 (#9846e).  Given that your receiver tube and barrel is Steyr (623 proofed) and in the "e" block as well, I'd say it is from a 1941 production gun.  It would be interesting to see how far off the lower is from the upper.

[Lewisfan]

Lower is a bnz 41 date with 3 numbers and an "l" (same as pics that you posted).  Question remains - how to date a receiver without a matching lower?  

Another note is that even though the matching barrel / barrel nut have the 6-face nut (vs later 2 "flats"), the receiver does have the creases top and bottom at the trunnion.  I read another recent post that states this was done on "later" guns as a more efficient method to press in the trunnion. Although the same post notes that this usually is seen with the 2-face barrel nut (also supposed to simplify production).  Any clues to date the receiver are appreciated!

[Rekraps]

8 hours ago, Lewisfan said:

Lower is a bnz 41 date with 3 numbers and an "l" (same as pics that you posted).  Question remains - how to date a receiver without a matching lower?  

Another note is that even though the matching barrel / barrel nut have the 6-face nut (vs later 2 "flats"), the receiver does have the creases top and bottom at the trunnion.  I read another recent post that states this was done on "later" guns as a more efficient method to press in the trunnion. Although the same post notes that this usually is seen with the 2-face barrel nut (also supposed to simplify production).  Any clues to date the receiver are appreciated!

I don't think you will be able to do so. The Germans used a four digit plus letter production code that repeated each year. Unless you have the matching lower with matching SN, you will not be able to do so. So, find the Lower!

[TSMGguy]

Right. All that can be said of the lower in question is that it was made by Steyer. Good photos might yield other clues.

[Rekraps]

16 hours ago, MS Collector said:

Here is my bnz41 (#9846e).  Given that your receiver tube and barrel is Steyr (623 proofed) and in the "e" block as well, I'd say it is from a 1941 production gun.  It would be interesting to see how far off the lower is from the upper.

My all matching bnz41 is same month production, only about 200 off from yours!