External Compatibility Thread

Discussion in 'Gun Building, Modifications & Repairs' started by wetpee, Jun 11, 2021.

  1. wetpee

    wetpee Active Member

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    So from my understanding, there are 3 or 4 different barrel nut specs..
    • VFC
    • G&P/TM
    • G&G
    • Real Steel
    Does anyone have the exact thread specs for each?

    I have a G&G plastic body looking to take a real steel AR-15 handguard. I tried to measure the threads on the G&G receiver and I think I'm looking at M31x1.5mm (metric). Real steel AR-15 is 1-1/4"x18 Threads Per Inch (SAE). Can I just cut new threads on the receiver or barrel nut and expect it to hold up fine?
    For reference, this barrel nut looks identical to the one I'm working with, but has G&P/TM spec threads:
    Madbull Barrel Nut for Noveske NSR Airsoft Rail Systems
     
  2. Guges Mk3

    Guges Mk3 Administrator Staff Member Administrator Supporting Member Lifetime Supporter

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    Actually it's two, might be 3 with old ICS.

    G&P/TM/VFC/RS are essentially the same. However, the Airsoft nuts I have encountered are just not threaded all the way and you need a tap to take it to 7 threads and put the Airsoft part on to a RS receiver.

    I have put Spec'd barrel nuts from Dytac (same OEM as G&P), TM Spec, PTW Spec and VFC Spec rails on RS uppers.
     

  3. wetpee

    wetpee Active Member

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    RS as in real steel or Real Sword? And so is G&G TM spec? Is this ARP9 receiver an oddball? The threads aren't cut all the way to the receiver so theres a gap between the handguard and the receiver. Even if the receiver threads went all the way to the receiver, the nut can just spin since there's nothing to lock it in place.
     
  4. Guges Mk3

    Guges Mk3 Administrator Staff Member Administrator Supporting Member Lifetime Supporter

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    Real Steel. Real Sword doesn't have anything that use AR parts.

    G&G May have shifted to "common" Spec threads on some models. I have not conformed that yet...
     
  5. aotsukisho

    aotsukisho Well-Known Member

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    Armalite spec is 1-1/4"x18tpi
    TM AEG spec is supposedly 31.8x1.5mm, I have not confirmed the measurements but it is 'close but not close enough' to AR-15 spec

    Any plastic receiver AEG can take real steel barrel nuts no modifications since the steel barrel nuts will thread themselves, I have run multiple G&G CM16s this way.
     
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  6. wetpee

    wetpee Active Member

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    I assume you used a spacer of sorts to fill the gap then since the threads end short of the receiver?
     
  7. aotsukisho

    aotsukisho Well-Known Member

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    It's true that the barrel nuts are designed for a shorter threaded portion, but I use freefloat rails on them and they tend to fit well in most cases. The only issue I've had is with repro DD Lite rail

    [​IMG]
    Note the gap between the top rail, if I ground down the area where the outer barrel rests on the gap would disappear - although I don't have the tools to ensure that the resulting surface would be flat and support the outer barrel straight, so I chose not to.

    [​IMG]
    Others work just fine. Same receiver set as the previous photo

    [​IMG]
    ARP9 has no problem with them either
     
  8. wetpee

    wetpee Active Member

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    Whaaaat the frick man.. I guess the real issue is the rail this guy got has no way of locking itself in place. The gap I was working with was similar in size to whats shown with that DD rail, maybe a little bigger.
    20210601_001444.jpg
    The general takeaway I'm seeing here is that most AEG M4 barrel nut specs are are the same, except G&G? What about AEG M4 outer barrels? I know Buffer tubes and their respective mounting points on the lower receivers keep seeing more and more changes but any general insights or common shared specs here would be cool.
    Also, GBBR M4 external specs?
     
    Last edited: Jun 30, 2021
  9. wetpee

    wetpee Active Member

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    Little off-topic but I don't want to start a new thread for this:
    VFC Avalon MK18 isn't playing nice with Retro Arms V2 gearbox. I'm REALLY not keen on making permanent modifications to this gearbox or receiver set. I've heard there's a VFC specific RA V2 gearbox, and maybe that would be the best option for this RIF, but I've been wanting something with some nice trademarks that are more fitting for a Mk18 style replica and this VFC has been nothing but problems for me since i got it.

    I'm looking at a few options for new external sets, namely King Arms and G&P with Colt and Daniel Defense trademarks, respectively. However, I've also found a Systema M4 (non-PTW) with Hurricane steel receivers with Colt trades. Would the RA gearbox drop in nicely with any of these and still allow me proper charging handle/mock bolt function? Could I pick up just a KA or G&P receiver set and use the VFC DD rail, outer barrel (with mock gas block + tube), and buffer tube? Other than having a good quality external set, I mostly care about whether I can use my VFC DD rail and fit a Turnigy Nano-tech 3S 25-50C 1.2Ah pack in the buffer tube.
    Dimensions of the pack: ~15.5x21x1.5cm plus space for wiring.
    Pics of the Systema:
    Screenshot_20210630-113447_HopUp.jpg Screenshot_20210630-113443_HopUp.jpg Screenshot_20210630-113438_HopUp.jpg Screenshot_20210630-113433_HopUp.jpg
    My two favorite options right now are picking up this Systema, or buying a brand new EMG (King Arms) Mk18, but I like the color of my VFC DD rail. KA looks a lot lighter.
    EMG Colt Licensed M4 SOPMOD Block 2
    emg-85081a-3.jpeg
     
  10. Guges Mk3

    Guges Mk3 Administrator Staff Member Administrator Supporting Member Lifetime Supporter

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    Who told you the HurricanE Receiver is "Steel"? I have never heard of HurricanE making a steel receiver. Back in 2004-5 the three HurricanE bodies were: Colt, Bushmaster and I think "Marine", but they were alloy and not "steel".

    They had the tabs like a TM from the upper over the lower and people were breaking them off thinking you can slap them down, when in reality you had to slide them on.

    And that SystemA gear box is an after market gear box and not over very good quality alloy either. Motors were overpriced furnaces...and quite honestly...not worth 1/5th of the cost SystemA charged for them...
     
  11. aotsukisho

    aotsukisho Well-Known Member

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    I think most AR replicas outside of G&P use Marui/metric spec barrel nuts, at least in my experience:
    A&K
    CA
    G&G (one barrel nut was difficult to remove)
    GHK (WA/G&P outer barrels fit with some modification)
    JG (fit both metric/RS, likely just bad tolerance)
    KWA (unique outer barrel, very difficult to remove barrel nut used dremel instead)
    LT (gen2)
    SRC (metal insert in plastic receiver for outer barrel and nut, tight fit)
    TM NGRS (unique outer barrel)
    TM Zet (requires outer barrel collar or aftermarket outer barrel)

    I've used RS/imperial barrel nuts on the following, most needed die work. 1-1/4x18tpi, WD40 cutting fluid
    G&G
    GHK (used die)
    JG (see above)
    KWA (used die)
    TM Zet (used die)

    As mentioned above, KWA has their own unique outer barrels for AEG and GBB. TM NGRS has a unique outer barrel (with zero aftermarket options that I've seen). G&P has that tapered system they are offering, along with the 'Transformer' quick detach front ends.

    All of my TM-spec outer barrels fit in my TM-spec uppers, some were tight fits but none required fitment work.

    Most are interchangeable, but I did notice that KWA Ronin series does not accept buffer tubes from G&G/ACM as their lower receiver post 'wings' are just thick enough to reject other brands I've tried.

    I'm surprised nobody has done a spacer to allow 'short post' type buffer tubes to be used on Marui-spec long post lowers. I asked a friend to 3d print me one but he misunderstood and just printed a post spacer rather than an internal shim for the buffer tube washer to hold.
     
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  12. Guges Mk3

    Guges Mk3 Administrator Staff Member Administrator Supporting Member Lifetime Supporter

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    You can add VFC, Dytac aftermarkets and PTW to the RS category.

    G&P is RS spec...just need tap out the last 4 threads....

    I have an old Dytac Water dipped keymod rail going on a real 300BLK AR build now and it's using the barrel nuts that came with the barrel. Screwed right on and I didn't even have to shim it.
     
    Last edited: Jul 16, 2021
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