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Thread: buffers w/non-milspec barrel ports

  1. #11
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    Mike's article:

    http://www.defensereview.com/m4m4a1-...yre-our-fault/

    See sub-sec # 1 (asterisk at the end) for this quote:

    "(*The rifle must have a mil-spec gas port and a barrel of 14.5” or 16” with carbine gas system. On mid-length gas system guns, use the Sprinco standard CAR-15 spring. This spring and heavy buffer do not consistently work in Rock River Arms rifles, from my experience.)"

    Knowing what we all know about RRA's gaping gas port sizes, I think it's logical to infer that their chambers tend to be tight. Somebody please correct me if I'm coming to an incorrect conclusion.

  2. #12
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    Quote Originally Posted by Magic_Salad0892 View Post
    I'd suspect that port to be somewhere in the .080'' range, and as high as .093'' from what I know.
    Is this size true for most M4's or are there to many variances out there. As there are company's that make AR's. I was just curious about this as I have never really paid attention to the gas port size.
    WFD
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  3. #13
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    I don't intened to keep it - I had been talking about doing this length and a friend said I could borrow an upper he has had for a little while. If I like it, I'll buy my own, probably a bravo company.

    He's been running it on his lower with just a carbine buffer on a pistol lower

    I have a carbine buffer, though I think that's probably a bad idea, and an H. I think I may go ahead and buy an H2, and then just try all three and see how it runs on them all - it will be interesting to find out anyways, and spare buffer won't be a bad thing!

  4. #14
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    Quote Originally Posted by 87GN View Post
    I would shoot it with that and see what it does.

    Or pull the FSB and mic the port. Life's too short to play what ifs.

  5. #15
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    I haven't pulled this exact one off, but several sources indiacte it should be .080 to .081

    I ordered an H2 from bravo company, will try that and see if it locks back on an empty mag, and if not then I'll experiment and see what happens from there. Or at least that's my plan at this point, unless someone sees/knows something I don't.

  6. #16
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    Who said? Maybe you are taking something out of context? It matters if you are trying to get the proper buffer to keep it running- especially in an SBR.

    Quote Originally Posted by kartoffel View Post
    Hold on.... you're telling me gas port diameter matters?

    All this time reading M4C and The Chart, I thought it wasn't something we were supposed to worry our pretty heads over.



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  7. #17
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    Quote Originally Posted by kartoffel View Post
    Hold on.... you're telling me gas port diameter matters?

    All this time reading M4C and The Chart, I thought it wasn't something we were supposed to worry our pretty heads over.




    Im not an SME by any stretch but my personal theory is that a factory gun should be able to run smoothly on a a carbine or H1. Running an H2 or H3 with reliable operation would mean to me the gun is running with way too large of a gas port. Keep in mind I mostly use Colt recoil springs with some BCM ones tossed in that Ive gotten from time to time.


    If you can run an H3, and still getting reliable lock backs with 223 ammunition that gun is in a world of hurt sarcastically speaking.

  8. #18
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    Quote Originally Posted by Belmont31R View Post
    Im not an SME by any stretch but my personal theory is that a factory gun should be able to run smoothly on a a carbine or H1. Running an H2 or H3 with reliable operation would mean to me the gun is running with way too large of a gas port. Keep in mind I mostly use Colt recoil springs with some BCM ones tossed in that Ive gotten from time to time.


    If you can run an H3, and still getting reliable lock backs with 223 ammunition that gun is in a world of hurt sarcastically speaking.
    Ordinarily speaking, I agree with you.

    But, I have found that there are some parameters that can change the equation on a properly ported rifle.

    2 examples.

    1) My BCM 14.5" middy will run a 7.3oz SS-body buffer (from heavybuffers.net) AND a Blue springco spring or Tubbs flatwire spring as long as I use a NiB BCG. When I go back to a phosphated BCG, I'm left with an H3 on a std rate spring (that's only 100% on NATO ammo). I find myself settling on the H2 w/ the Tubbs for smoothness purposes despite being able to go much heavier. The H2 w/ the Tubbs is the smoothest combo on the return stroke during recoil (BCG going back into battery) and my micro jiggles the least when using this setup.

    2) The NGA X7 uses a Noveske 14.5"-middy afghan barrel (with a conservative GP size) and it runs either a springco Blue or Red with an H2. However, it also has a coated BCG (proprietary ceramic coating).

    Outside of these two examples, I generally agree with you.
    Last edited by BufordTJustice; 10-07-11 at 02:11.

  9. #19
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    Quote Originally Posted by steelonsteel View Post

    So I have an SBR upper, and Ive been loaned for a week or so a differant upper to try. Here's the rub - it's an 11.5" upper from Rock River Arms. Yeah, I know - not really top of the chart - but for the price [read; free] I'll play with it.

    Now, if I understand correctly, RRA tends to run their gas ports larger than mi-spec? Or perhaps I'm wrong on that?

    If that is so, then theoretically, I should be using a heavier buffer - like say an H2... correct?

    I have access to carbine and H buffers. But I'm wondering if shouldn't go ahead and buy the H2 for this, as I don't want to damage anything [since it's not really mine].

    If I run too light of a buffer things will slam around and could potentially amage something right? or is the only drawback higher recoil?
    If the upper is just to play around with, most likely you don't NEED to do anything.

    The upper will likely still operate, but will have high cycle speed.

    This tends to reduce reliability at every phase of the operating cycle.

    My general advise is that an H2 is good to have around and is my first choice in a CAR length RE.

    As pointed out by Todd long ago, the H2 has roughly the same moving mass as the original rifle buffer that the system was designed with and is generally sufficient to eliminate bolt bounce.
    Black River Tactical
    BRT OPTIMUM HFCL Barrels - Hammer Forged Chrome Lined 11.5", 12.5", 14.5"
    BRT OPTIMUM Barrels - 16" MPR, 14.5" MPC, 12.5" MRC, 11.5" CQB, 9" PDW
    BRT EZTUNE Preset Gas Tubes - CAR and MID
    BRT Covert Comps 7.62, 5.56, 6X, 9mm
    BRT MarkBlue Gas Tubes - BRT EXT, EXC and PDW Lengths
    BRT MicroPin Gas Blocks - .750" & .625"
    BRT MicroTUNE Adjustable Gas Blocks
    BRT CustomTUNE Gas Ports

  10. #20
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    Quote Originally Posted by DemonRat View Post
    Is this size true for most M4's or are there to many variances out there. As there are company's that make AR's. I was just curious about this as I have never really paid attention to the gas port size.
    Milspec carbine gas is .062'' for a 14.5'' gun.

    A Colt Commando should have .071, or so.

    RRA uses anywhere from .080-.093''...

    Also, Iraqgunz:

    Every time you make that analogy, you use a different porn actress name:

    How much ****ing porn do you watch, dude?...
    We miss you, AC.
    We miss you, ToddG.

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