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Thread: Sten mags not feeding

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    Registered User xdamagedx's Avatar
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    Sten mags not feeding

    I'm using Sten magazines for my Lage upper. They ran great until this spring. For the past 2 years they've been flawless. Now I load them to 30, and even stripping the ammo out by hand, the bullets nosedive. When I get down to about 10-15 left they straighten out and run fine. I didn't let them sit loaded with all kinds of spring pressure, I didn't abuse them. I've tried pinching the feed lips closed, and also opening them. I've tried using dry lube and wet lube. I made sure they were cleaned out. I also broke down and bought new springs from RTG. It seems they just no longer want to work. Any ideas?

  2. #2
    Registered User GeneralPurpose's Avatar
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    You could try to find a Sten magazine repair tool. Sten mags are finicky about their dimensions being correct, but if they are correct I've found them to be flawless.

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    Registered User DINK's Avatar
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    If I'm reading your post correctly, you are experiencing the same problem in all the mags you use with one particular upper. If that's the case, I would look at the common denominator, which is the upper. Personally, I would try throwing a fresh spring set in the Lage upper and see what happens. If you have been running an SMG for a couple of years, the springs might be getting tired and not presenting the ammo to the chamber like they used to. According to people who know a lot more about it than I do, it isn't being compressed that wears springs out- it's the cycle of compression and relaxation over and over that wears them out. Your magazine springs go through one cycle every time you load and empty a magazine, but the recoil spring in the upper does it thirty times.

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    Stripping the ammo by hand would indicate it's a magazine related problem. Just a passing thought: Maybe it's the ammo?

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    Quote Originally Posted by Starvingboy View Post
    Maybe it's the ammo?
    That’s a likely possibility.

    Ammo manufacturers are rushing to get it out the door while demand is crazy high. I am seeing all kinds of issues. No primer, primers upside-down, primers not seated, bullets shoved deep into the case and squib loads. And that’s with “quality ammo”.

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    Registered User xdamagedx's Avatar
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    Quote Originally Posted by GeneralPurpose View Post
    You could try to find a Sten magazine repair tool. Sten mags are finicky about their dimensions being correct, but if they are correct I've found them to be flawless.
    The bit of research I did wasnt too helpful. First problem being: the repair tool set is extremely hard to find. Second problem is it seems to be hit or miss on getting the job done.

    Quote Originally Posted by DINK View Post
    If that's the case, I would look at the common denominator, which is the upper.
    Thats a fair guess also. My only problem with it is the following: my shockwaves, coffins and drums aren't being effected.

    Ammo: see above. My other magazine types don't seem to be effected.
    I've ordered more shockwaves to help fill the "backup" gaps. Klyph is letting me borrow his modified Sten mags as backups as well. And Cory has offered to let me borrow more mags also. I'm set on mags, I just hate knowing these things are sitting here with a (probably) simple problem I'm overlooking.

  7. #7
    Registered User xdamagedx's Avatar
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    Also: this is a set of 5 mags. 1 of the 5 still runs and feeds fine. The other 4 are having the problem.

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    I have HALF of the Sten mag repair tool, you're welcome to borrow it. I have the "Outside" part, and am looking for the "inside" part if anyone has a spare.

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    chili17's Avatar
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    sounds like the front of the lips need to be pushed in.
    Chris Hipes
    Hipes Consulting Services LLC
    FFL/SOT 07/02
    poulan10takethisoutsoidonotgetmorespam@yahoo.com
    North Texas

  10. #10
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    The thin feed lips on Sten mags spread, especially when fully loaded or stored loaded. As someone mentioned earlier, once the feed angle is correct they are pretty reliable.
    I have posted this link before, but if you have not seen it...there is info and pictures of the Brit tools. BRP (?) has them.

    https://www.smallarmsreview.com/disp...darticles=1974

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    I have an Olympic Arms AR upper that uses Sten mags. I have found that the lips spread with use and need to be worked on to get the correct feed angle every once in a while.

  12. #12
    Registered User DINK's Avatar
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    If you have one mag that still works fine, you need to use it as the template and adjust all the others until the ammo is presented EXACTLY the same way. Make an angle guide with a piece of thin material like wood veneer or Formica that you can lay along the back of the magazine that will lay along the top of the round in the good magazine also, then use that to adjust the other mags until the angle is exactly the same. Also adjust the lips until the same amount of cartridge is sticking up out of the magazine.

    Use a small stone to polish the inside edges of the feed lips where they touch the sides of the cartridges. Don't remove any more steel than you have to, but remove any dings or dents that might catch on the rims of the cartridges as they slide forward.

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