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MilSpec or Comm Tube on my AR?

Discussion in 'Rifle Country' started by HMMurdock, Mar 24, 2009.

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  1. HMMurdock

    HMMurdock Member

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    I am looking at getting a Magpul CTR stock (or the MOE, when I figure out what the difference is) and it says it is for MilSpec tubes, not Commerical. I have a Bushmaster AR I recently bought at a shop, new, with nothing changed on it. How do I know if I have a commerical or MilSpec tube?
     
  2. Gary G23

    Gary G23 Member

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    You can measure the diameter.
    1.14" is milspec
    1.17" is commercial

    Every Bushy I have seen has been commercial.
     
  3. tunnug

    tunnug Member

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    Easiest way to tell without measurement, take a look at the threads, if they stick out past the tube it's milspec, if they're even with the tube it's commercial.
     
  4. bushmasterar15

    bushmasterar15 Member

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    Every bushy that I've had had a commercial tube on it.
     
  5. SimpleIsGood229

    SimpleIsGood229 Member

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    Mil-spec tubes are generally 4- or 5-position, while commercial-spec are generally 6-position, if I'm not mistaken.

    The CTR has a friction lock which removes any play between the stock and buffer tube, while the MOE does not. I highly recommend the CTR. I love mine.
     
  6. MCMXI

    MCMXI Member

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  7. Zach S

    Zach S Member

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    BM uses commercial stocks. You can either find a commercial CTR, or swap the buffertube out for a mil-spec (I used a stag).

    As stated above, the CTR has a friction lock that locks up solid, the MOE lacks that friction lock, it just looks like the CTR, and rattles like an M4.

    For future reference:

    Mil-spec:
    Threads larger than the buffertube. If you have calipers, the tube is 1.140 diameter, the threads are 1.188, +/- about .010" maybe .015"
    4 or 5 position, although I think stags are 6. (edit: just checked mine, its 6)
    The back is straight, doesn't sit flush with the stock when it collapsed.


    Commercial:
    Threads and tube are the same size, 1.170 (+/- .010)
    The back is normally angled to match the stock, and is almost flush when collapsed.
    6 position

    CMMG used to use a cross breed between the two. The diameter and threads were mil-spec, but it was 6 position and has the slanted back to match the stock, like the commercial buffer tube. I believe they use mil-spec 5 pos tubes now.
     
  8. MCMXI

    MCMXI Member

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    I stopped by my local gun shop this morning to buy a Troy front sight (HK folding battle sight) and ending up buying a bunch of other stuff too including a Vltor Emod buttstock (commercial) for my Bushmaster lower/POF upper along with 5 MagLevel™ PMAG™ magazines and a MagPul MOE grip. :D I wanted/needed the other items anyway so I figured I might as well get them while I was there.

    :)
     
  9. Pickles

    Pickles Member

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    Are Rock River Arms LAR-15's usually commercial, specifically the Entry Tactical?

    <sorry in advance for dumb question, my Entry Tactical is currently in the mail on it's way to a local FFL>
     
  10. Zach S

    Zach S Member

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    Commercial.

    Commerical:

    RRA
    Bushmaster
    DPMS
    Double Star
    Sabre Defense(?)

    Mil-Spec:
    CMMG
    Stag
    Noveske
    CD
    S&W
    LMT
    Colt
    Spike's Tactical (I think)

    I dont know about Armalite (mil-spec, I think), and I dont feel like searching for the much hated chart.

    On a side note, it would appear that Mil Spec buffer tubes are becoming the standard, with only a few companies not using them.

    If you by a no name collapsible stock, assume its a commercial. Most aftermarket mil spec stocks are advertised as such.
     
    Last edited: Apr 15, 2009
  11. yehork

    yehork Member

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    As a side note, DPMS offers both Commercial and Mil-Spec tubes, so you could have either if you have a DPMS.

    Our base model rifles come with the commercial tube, except the Mark 12 which has a Mil-Spec and the Mil-Spec tube is an upgrade for others.

    The easiest way to tell the difference on a DPMS is the commercial tube we sell is a 6 position and the Mil-Spec is a 5 position (including fully open and fully closed).
     
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