Mp40 Mags Feeding Problems

[Uncle Dudley]

:banghead: I have several MP 40 magazines that work very well and several that seem to feed the first or second round too low and jam. Does anybody know how to check, tweek, modify, file, or whatever to make the mags lips feed properly? Any help is greatly appreciated.

[emmagee1917]

Get a good pair of calipers. You have mags that work and those that don't in your gun , therefor your task is simple. Compare the lips , spaces , how the round sets to be fed , distance to locking grooves , general fit in the mag well , of those that work to those that don't , then change what doesn't match .

Chris

[TSMGguy]

You probably first want to rule out ammo as the problem. Functionality can be compromised if ammo is not 124 gr. full power NATO spec (M882, IIRC) or equivalant. There are two springs at work in the telescoping spring housing, the recoil spring and the buffer spring. With the gun unloaded, pull the bolt fully rearward. As the bolt nears full travel, you'll feel the greater resistance of the buffer spring. During firing, both springs have to be fully compressed or the bolt may not achieve the forward velocity necessary for positive functioning. Underloaded 115 gr. ammo may not accomplish this.

 

My favorite ammo for the MP40? Russian steel cased 124 gr., though I am having trouble finding it these days. The Russians seem to be producing 115 gr. like everyone else.

 

I've noticed over the years that the fit and general quality of German wartime MP40 magazines was not consistant. I've even found a few that would not fit into the mag well of my BNZ 41 (Steyr) gun at all! Original loaders could not be used with these and some other magazines, as well. I believe that the best quality and most consistant fit is to be found with Steyr-made magazines which were coded 98E, or after 1941, KUR. '40 dated 98E mags are slab sided, and ribbed for '41 and later. All carry WaA815 stemples on all parts. After trading or selling off mags by other manufacturers, I now have 10 excellent 98E magazines with '40 or '41 dates, all of which fit and function perfectly (slicker than snot!) with the proper ammo. I keep all lightly greased and clean internally.

 

The MP40 was not a fast firing weapon like the M1 or '28A1 Thompsons. Today, you're after reliability, not speed. Something under 600 RPM is about right, about the same as a Uzi. With the proper trigger control, you should easily be able to squeeze off single rounds with any properly functioning MP40.

 

FWIW.

[Uncle Dudley]

Thanks to both of you. Good info. I have the "good" mags working great with both 124 and 115 bullets. The bad mags seem to be a feed lip problem, so I'll get the calipers out. The gun runs fantastic with the good mags, and seems around 400 to 500 RPM. It's fun to shoot the MP40 at the slower rate and smaller cartridge, compared to the TSMG, and be able to drop those 1-2-or 3 round bursts right on target.

 

My MP40 is all number matching, and the Nazi that had it, couldn't have had it for long (1942 Haenel), as it is in very nice shape.

I read somewhere, maybe Frank's book, that German soldiers would keep track of magazines that fed reliably and keep those for combat use.

 

U D

[JTinIN]

Bring up an old posting, but how did adjusting the mags turn out?

 

I have at times on single feed mags had to polish the inside of the feed lips a little, in particular if they have been re-finished.

 

Good Luck

[Uncle Dudley]

Bring up an old posting, but how did adjusting the mags turn out?

 

I have at times on single feed mags had to polish the inside of the feed lips a little, in particular if they have been re-finished.

 

Good Luck

 

 

That may be a better solution. I didn't want to get aggressive filing on the mags, as they seem to be really close in measurement. I have only been shooting the mags that work consistently. The others are set aside.

 

Thanks,

 

UD

[mnshooter]

Post #3 seems the best advice.

After reading TSMG's post (and having an identical MP-40), I followed the same route, finally acquiring all the 98E41 mags I can use, and am getting 99.9% function, which from some accounts is better than in wartime use.

Even the lighter 115 gr. loads, which did not want to run with the other mags, -now run very well.

Edited April 12, 2012 by mnshooter

[Uncle Dudley]

Post #3 seems the best advice.

After reading TSMG's post (and having an identical MP-40), I followed the same route, finally acquiring all the 98E41 mags I can use, and am getting 99.9% function, which from some accounts is better than in wartime use.

Even the lighter 115 gr. loads, which did not want to run with the other mags, -now run very well.

 

 

All my mags have

 

MP41

 

patent schmieser

 

HAENEL (in an arrow)

 

What is a source for the 98E41 mags?

http://img.photobucket.com/albums/v104/overspray/th_PaulGMGshoot002.jpg

[TSMGguy]

I broke open a case of Federal M882 ball ammo when I ran low on Russian Ulyanovsk 124 gr. 9mm. This is the full power stuff with NATO head stamps that occasionally shows up in bulk, though it's probably a little expensive for general blasting. Function is perfect. I also tried some milsurp Argentine ball ammo, marked FMSF 79. I got failures to feed when the bullets tended to lodge and jam on the upper rear of the breech. This ammo has a bullet that's very rounded in profile when compared to the more triangular original WWII German, Russian, and M882. The only pieces in which I can get the Argentine to feed reliably are in an Argentine FMAP High Power (makes sense!)and a Spanish Star Model B.

 

Collecting the 98E and kur marked magazines was just a long process of hit and miss over many years until last year when a Gunbroker seller in Germany had them in original unissued brand new condition. I bought three each, marked 40 and 41. End of quest! The 98E 40 mags are slab sided, having never been converted to the ribbed mag bodies. They seem to feed just as well.

[Uncle Dudley]

I have a 98E slab sided mag coming from Norway. I'll see if it works better. It should be here in the next week.

 

UD

[mnshooter]

Post #3 seems the best advice.

After reading TSMG's post (and having an identical MP-40), I followed the same route, finally acquiring all the 98E41 mags I can use, and am getting 99.9% function, which from some accounts is better than in wartime use.

Even the lighter 115 gr. loads, which did not want to run with the other mags, -now run very well.

 

 

All my mags have

 

MP41

 

patent schmieser

 

HAENEL (in an arrow)

 

What is a source for the 98E41 mags?

http://img.photobucket.com/albums/v104/overspray/th_PaulGMGshoot002.jpg

 

My apologies for not reading this sooner. I acquired the 98E41 magazines probably the same way as TSMG, just kept watching the for sale boards, and sooner (and) later, some of the correct magazines showed up.

Posing a WTB on the Sturmgewher or Subguns ads doesn't cost anything (except a donation if you're inclined), and might net you some magazines. The rest of my experience with fit and function so closely mirrors TSMG's post that it would be redundant.

As I'm sure you know, your magazines were actually intended for the imagined MP41 commercial market, hence the Schmeisser name at the bottom.

If you do want to only have more Schmeisser marked MP41 magazines, I do have one that has pretty good finish, but a lot of fine little dents, too small to affect functioning, but sure doesn't look as good as it would without them. I would sell it for $60.00 shipped. I did find it is a tighter fit in the mag well than the other earlier magazines, so if you have a problem with some magazines feeling loose, this one may fit better. If you're interested, PM me your email address, and I will send some photos.

Marc