Tune/Repair mp40 magazines. Need help

[TSMGguy]

TSMGuy...what brand of 124gr nato do you run?? Thx

 

Hi, I've had good luck with Federal or Winchester M882. Federal runs the Lake City ammunition plant. Their M882 is often to be had in cases of 1,000 rounds in 50 rd. boxes, or just loose packed. Look for the STANAG cross-within-a-circle on the cartridge case. This is quality stuff.

[RogerD]

MP-40 magazine question. I was at a gun show yesterday and noticed a pretty nice magazine. It was stamped 98E 40. What caught my attention was the font was different and smaller from my others. Additionally the markings were heavily embossed. This made me a bit suspicious but I got it for a very good price. The other marking appeared correct. Is this some early war manufacturing anomaly?New mag on the left.

Edited August 5, 2018 by RogerD

[huggytree]

You mean the the waffen marks??

 

Qc stamp at the factory. Military acceptance stamps. Each inspector had his own number

[RogerD]

All the markings on the top of the magazine were deeply imprinted into the metal with a different font/punch that I had never seen before where the 98E and date is marked. QC marks are standard but again deeply imprinted in the metal. Just curious about the deviation.

[RogerD]

All the markings on the top of the magazine were deeply imprinted into the metal with a different font/punch that I had never seen before where the 98E and date is marked. QC marks are standard but again deeply imprinted in the metal. Just curious about the deviation.

 

Not sure why this is coming up in duplicate forgive me if I'm screwing this up since I don't know how to delete it.

Edited August 6, 2018 by RogerD

[TSMGguy]

RogerD, the mag is legit. The markings are depressed because these were applied by hand and someone struck the die a bit too hard. The mag will have two WaA815 (Steyr) markings as well. We know that the mag was originally produced as a slab sided mag because an additional WaA marking was applied above the others when the ribs were added to the mag body. These ribs supposedly reduced internal friction and contributed to reliability. Apparently, three different firms did this work. The slab sided mags you find today escaped this mod somehow, just as some early guns were never modified with a sliding safety in place of the hook-type cocking handle.

 

I've found that Steyr 98E and kur (new code after early 1942) mags have the best and most consistent quality. I've gotten rid of all my mags from other makers and kept only these for my sole remaining MP-40, an all matching bnz 41. Over the years many of the internals got swapped with parts from other manufacturers, but all of the mags work fine since the bodies are of such good quality.

 

I bought six of the rare 98E 42 mags from a seller in Poland who claimed that they were in original brand new condition, having just been broken out of the original WWII crate. Sure enough, each mag had every part marked WaA815. They're literally perfect, with deep, matte bluing, and not a scratch on any of them. Original quality was superb.

Edited August 6, 2018 by TSMGguy

[imageaudio]

Range Update,

 

Good advise Petroleum one. I ran a consistent setup in my last round of tests to isolate the problem mags. After my new Mag Springs arrived from Lee Tool & Machine I installed them in the previously problem mags. They are supposed to be plus power and had 3-7 more coils than the variety of springs they replaced. Below is a summary of where I"m at and what i've learned.

 

Using PPU 9mm 115 grain to test all the problem mags, using the original German bolt/pin combo, the new springs solved the issue in 5 of my 8 mags. Of the 3 mags that did not run, they all experienced the same problem, which was a failure to feed. In all instances, the round either failed to be stripped from the mag feed lips or it was stripped and did not chamber. When stripped and it did not chamber, the bullet was set back into the cartridge.

 

 

After demonstrating that most of my mags now ran using the PPU ammo using the original German bolt, I wondered if the stronger springs in the FBP bolt would have enough power to successfully strip the rounds from the magazine. After installing the FBP bolt, the 3 remaining problem mags still had the same failure to feed issues. I then ran the good mags using the PPU ammo and all functioned perfectly. No mag dumps, sear caught successfully every time I released the trigger, etc.

 

Conclusion: The new mag springs solved most of the problems. I may play around with the feed lips on the non-functioning mags or just pass them along to other collectors who need them for non-firing replica guns, etc. The other good news is that my FBP bolt functions perfectly in my MP40 without any modifications.

 

Thanks all who contributed their knowledge to this post.

[Petroleum 1]

Those rounds are nose diving and probably hitting the lower part of the feed lip jamming the bullet back into the case. The mags that do not feed are they sitting up in the magwell at the same height as the ones that work?? Is the catch worn and the mag has up and down play?

[huggytree]

i had 1 mag that just would run..i sold it, moved on

 

had another that would leave the last 1-2 rounds in the mag....found out about the follower issue you found..some convex, some concave....i swapped out the follower from a convex to a spare concave i had and it fixed the issue...no idea why they made concave side wall followers...makes no sense

 

most of my mags are in NOS condition....the few that werent needed the spare springs...i think i used 3 of them total....ive really only had 1 bad mag out of the 9 ive tried and used

 

easier to sell the bad one and move on vs trying to tweak it.....i always buy 15-20 mags so i can always have spares...bergflak sells NOS followers...might be an easy way to fix mags with minimal cost if you have more convex ones

 

i also tossed the Wolf spring kit in my main spring housing(or whatever its called)....wondered if it would slow down the ROF or make 115 grain not function...nope-worked flawless.....also have played with the FPB bolt....it runs through my tube like sandpaper...also rubs my ejector a bit ....it does catch the sear nicely though....wondering if i try to run it if it will wear on my bolt or wear on my tube...id hope the bolt is softer????