Magazines will not lock up in AR 15

Discussion in 'AR-15 Discussion' started by KHickam, Jun 5, 2016.

  1. KHickam

    KHickam Member

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    I just finished building a new AR 15 using Anderson and Spikes parts kit - took it to the range today and discovered that plastic/polymer magazines will not lock into the magazine well - However, aluminum magazines do - I tried polymer magazines from Tapco, Troy and P-Mags and did not effect it - I even tried dremeling the magazine catch recess on the magazines to see if that was the problem - still no effect.

    However, aluminum magazines from Blackhawk, USGI, and Red Jacket work fine - no problems locking solidly in the well.

    I tried backing out the magazine catch/release button to see if that would help - it did not

    Suggestions?
     
  2. kbd512

    kbd512 Well-Known Member Lifetime Supporter

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    Will the polymer magazines seat in the mag well when unloaded?

    Edit: Is the bolt forward or locked back when you're trying to seat the magazine?
     

  3. KHickam

    KHickam Member

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    No

    I tried both ways - bolt open - bolt closed will not lock

    aluminum magazines work no matter what way I try them
     
  4. kbd512

    kbd512 Well-Known Member Lifetime Supporter

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    It could be an improperly machined magazine well (magazine catch hole machined slightly off center from where it should have been) or an improperly machined magazine catch (more probable).

    I usually blame the magazines, but I doubt that three different polymer magazine manufacturers all happened to produce out-of-spec magazines that you just happened to get your hands on.

    What's the make and model of your rifle? Or was it assembled from a parts kit? Are you the original owner?
     
  5. KHickam

    KHickam Member

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    Parts gun

    Anderson stripped lower, Anderson M4 Upper - Spikes lower parts kit - I just assembled it a couple days ago - took it to the range today - shoots great (well as well as my 50 yr old eyes can through a peep sight) upper was military zero I am sure because after shooting it - I saw it was printing like others I had built or were rack guns - took my military adjustments 8 clicks down, 2 left and it came right in.

    5th build I have done with no problems before like this - and as I said aluminum mags lock in fine
     
  6. kbd512

    kbd512 Well-Known Member Lifetime Supporter

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    I'm not sure what to tell you. This sounds like a magazine catch or magazine well dimensioning / machining problem to me. That's not likely to be a simple and easy problem to fix. That rifle is probably going to be an aluminum USGI mag-only rifle.
     
  7. partdeux

    partdeux Well-Known Member

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    Internet is your friend :)

    Search on the brand you have and see if there are any reported problems. I recently took an AR class and struggled all class, until I tried a different brand I happened to bring. NO issues! Came home, searchd on the brand, and six magazines are now in the land fill.
     
  8. FrontierTCB

    FrontierTCB Active Member

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    Have you tried screwing the mag catch in where it would pull farther into the mag well. Also if you remove the upper and insert a mag in the lower you can have a better view of what is going on from above.


    Sent from a phone I can use to do my taxes, but can't make a damn call.
     
  9. KHickam

    KHickam Member

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    Done that too

    Yes, I did both - still no effect.
     
  10. fsted2a

    fsted2a Active Member

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    May have had too much material removed during remanufacturing process of the lower. Polymer mags will usually work when it's too tight for USGI mags.
     
  11. Quentin

    Quentin New Member

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    A guy I trust at a LGS said they quit carrying Anderson stripped lowers because too many were out of spec. Magwell - and takedown and trigger group holes. Most were ok and the price was good but not worth the aggravation of dealing with burned customers. Too bad, they look good.
     
  12. KHickam

    KHickam Member

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    New magazine catch installed - not a problem works awesome now
     
  13. FrontierTCB

    FrontierTCB Active Member

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    Interesting, not Anderson's fault in this case. Glad it was an easy fix for ya!


    Sent from a phone I can use to do my taxes, but can't make a damn call.
     
    Last edited: Jun 7, 2016
  14. Quentin

    Quentin New Member

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    Glad it was a cheap and easy fix!