What can you tell me about this upper?
 

I have this 9mm upper that Dad brought home from WWII. The story was that he was only allowed to bring home one pistol and 2 rifles. He brought home an Artillery Model Luger and this upper, plus a VZ24 and a G33/40. Serial numbers on the extractor and toggle don't match the receiver and barrel. What does the "42" mean? It's not stamped "DWM" like my Artillery Model.

There are some proof stamps on the right side, forward, but I can't capture them with this camera.

I want to slip it on my Commercial Model Alphabet Series P08 (.30 Luger) when I want to fire 9mm with that frame.

You've got what is most likely a DWM or Erfurt receiver and barrel with a Mauser made toggle train.

I can't make out the full date of the receiver in your picture. I can read "191" but not the last digit.

The proofs will tell which factory made the receiver and barrel.

The "42" is a concealment code used by Mauser in about 1940.

Since the toggle train and receiver were not manufactured together, you may need to pay attention to the headspace and fit. It's possible that this was done when they were originally combined.

In order to use this 9mm upper with your .30 Luger Alphabet Commercial DWM frame, you'll probably have to replace the recoil spring to handle the larger recoil power of the 9mm and possibly do some trigger system fitting.

I would not alter the DWM's side plate or trigger bar. If you find that the trigger of the assembled combination doesn't work, I would obtain an additional trigger plate, trigger and transfer bar. Don't do anything to alter the parts and operation of the original Alphabet Commercial DWM.

Marc

What can you tell me about this upper?
 

Date stamp is 1917. Here's an image of the proof stamps on the side. Hope you can enlarge them to get a good read on them.

I know what you are wanting to do, and it can be done.....I did it. Since these lugers were all hand fitted when manufactured, you will need to check the parts of your upper receiver to your frame. Some need a fair amount of work to fit correctly, others, not so much. You may well need to play with springs(main) depending on what is currently in you Alphabet luger.

I found a 1939 receiver that had been rebarreled with a 5in bbl, and I fitted a complete Erfurt toggle train to it. I now can switch back and forth between the calibers. I am a reloader, so I have a load that requires no spring changes.

Good luck.

I believe that your receiver and barrel are Erfurt made.

Marc

You may get lucky..Just make the switch and see...

OK. Here's a follow-up, four months later. I slipped the 9mm upper that Dad brought home from WWII on the .30 Luger 1920's alphabet series commercial lower that I recently inherited. It slipped on easily enough, no binding or excessive play. I see what you meant about these pistols being hand fitted. I also tried installing the trigger, takedown lever and sideplate that Dad brought home with this upper. They binded (bound? JAMMED!) So I kept with the original commercial parts.

Next, I hand cycled a magazine full of 9mm ammo through it. No Problem!

Today, I took it to the range and gave it a dance. First I fired some .30 Luger (gun show reloads, uh-oh!) through it. One stovepipe and a failure to lock open on the final shot. Then I changed uppers and fired my own 9mm reloads (115 gr FMJ factory duplication loads) through it. Another stovepipe, but overall, the same results as the .30 Luger. So maybe I don't need to change mainsprings to fire 9mm after all?

One thing I noticed when firing both calibers: some times the trigger had a sweet pull and release, other times I had to squeeze it all the way to the stop AND THEN SOME! What's up with that?

G.T., do you want to weigh in on this?

You really should not be swapping a .30 cal. lower with a 9mm upper, unless you change recoil springs as well. The 9mm is more powerful than the 30 cal. and the weaker .30 cal. spring will cause malfunctions and possible damage to your pistol.

I am sorry, but I have to respectfully disagree with Alanint. In my "convertible" Alphabet Luger, I installed a new std. 9mm recoil/main spring, and with my 30 Luger ammo loaded to factory spec, it will function the same as the 9mm ammo. I also have a less stiff main/recoil spring, but I opted to try and error on the safe side.....and I believe that I was successful. If one were loading either or both rounds "soft", then you would most likely need to start changing some springs around.

This is some good information. So, to err on the side of caution, I should install a 9mm mainspring like this one http://www.gunpartscorp.com/Products/465390.htm Worst case scenario, it may not cycle .30 Luger ammo, but won't do any harm either. I always try to load to "Factory duplication" specs in my Lyman, FWIW.

I'm not sure why you are disagreeing, Richard, since you plainly state that you installed a 9mm spring, albeit "standard", in your convertible pistol. My concern is over firing 9mm loads, some perhaps hot, in a .30 cal. lower with the standard .30 cal. spring in it, which is what is being proposed.

Am I missing something?

No, you are not missing anything.....I guess my brain just read it different than the way you posted it. O.K., I don't disagree with you.....I like it better that way.

I don't know what poundage that spring actually is. I purchased my springs from Wolff Springs, and they will tell you what the std. spring weight is, and also offer a mainspring that is two(2) pounds lighter.