M4 "pigtail" gas tube modification?

Discussion in 'Gunsmithing' started by Lomotil, Dec 9, 2008.

  1. Lomotil

    Lomotil New Member

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    Dec 5, 2008
    The Alamo City
    Hi...

    Relatively new to the site, but wanted to ask opinions on a sales pitch thrown at me during a recent gun show.

    When I mentioned that I'd recently (the night before, oddly enough,) built an M4, a vendor asked if I'd "pigtailed" the gas tube (along with offering his gunsmithing services.)

    Apparently, the premise is that the platform and the round was specifically designed for a 20" barrel, and comparable gas tube length. His argument was that the shortened barrel of the M4 gave rise to compression issues, which would be rectified by extending, and looping, the gas return around the barrel, to simulate the original 20" length.

    He also credited misfires, jams, etc., with the shortened barrel & gas return system, but I'm not entirely convinced.

    Does anyone have any info or experience with either the rifle itself, or this particular modification to it?

    For reference: DPMS lower, 2 lb trigger, DPMS, chrome-moly M4 upper, 5.56, 1x9, and an itchy trigger finger. Only one round fired through it so far.

    I'm more familiar with my AK-47, and it's generous tolerances when it comes to various ammunition, etc. (not to imply that I don't maintain my guns.) - This is just the first AR-15 variant I've built, and I wonder if his claim has any merit, or if he was just trying to stir up business.

    Any info is greatly appreciated. :)
     


  2. My AR15 pistol had a larger hole under the gas block. I think someone was trying to make some money off of you though.
     
  3. TSU45

    TSU45 Active Member

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    Jun 6, 2008
    San Marcos, Tx
    I think that whole pigtail argument is a load of bulls#$@. I've never met anyone who actually has one of those gas tubes. My 14.5" works just fine without one.

    You should of asked him if the military "pigtails" the gas tubes on their thousands of M4's.
     
  4. TSU45

    TSU45 Active Member

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    Jun 6, 2008
    San Marcos, Tx
    Right.....Misfires from the shortened barrel and gas system.

    I get tired of that element of gun show gypsy dealers and their useless sales pitches. Did he offer you some Extreme Shock ammo as well? Cause it's the bestest and will probably get banned real soon. Lucky for you he's got 100rds left.
     
  5. Lomotil

    Lomotil New Member

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    Dec 5, 2008
    The Alamo City
    Thanks for all the replies, folks. I wasn't too sure about it, and had never heard of that problem before. He had his sales pitch down, though, and I couldn't help but get that feeling like I was someone that only knows how to put gas into a car, and the mechanic is trying to sell me a new flux capacitor that'll save me money somewhere down the line... :mad0025:

    Ha! Not exactly - but there were definitely those kinda people there... And the people were eating it up. I almost ordered a DPMS Kitty Kat 7" upper for a future project online a few weeks ago for somewhere around $600 - Saw the same damn thing (minus the quad-rail) with a price tag of over $1,000. I chuckled, as I moved to the next booth. Several hours later, it was gone. Simply amazing.

    This 'gas tube' guy's gimmick was selling what he called "Obama Tubes" - Insulated PVC pipe "time capsules" in varying sizes, for various sized weapons, in the event that all firearms are confiscated, and someone would feel more comfortable with theirs buried in the ground, rather than pointed between the eyes of whomever tries to collect them door-to-door. :fighting0002:
     
  6. lilricky2

    lilricky2 New Member

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    Aug 17, 2008
    S.E. Houston
    I do alot of AR work. The pigtail tube actually can solve a gas pressure issue but to arbitrarily stick one on an AR is preposterous. It can just as easily cause a problem. When set up correctly the platform works as well as anything out there. Whatever you do, don't make random chages to the gas system without understanding how it works. The number one problem I see is people drilling out the barrel gas port because of a percieved extraction problem. Guess what, overdrilling the gas port causes an extraction problem so people just keep making it larger thinking it needs more gas pressure. Test drive the rifle with good ammo and see how it functions before you make any changes. Just my 2 cents worth.

    Rick
     
  7. TSU45

    TSU45 Active Member

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    Jun 6, 2008
    San Marcos, Tx
    Did the bolt lock back on the empty mag when you fired the one test round? If it did then you are probably good to go on your gas system.
     
  8. kville79

    kville79 Active Member

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    May 24, 2008
    Austin
    The only thing you need to worry about the gas system is this... Keep it clean!
     
  9. idleprocess

    idleprocess Active Member

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    Feb 29, 2008
    DFW.com
    And how many rubes bought them on credit card? And were seen leaving the premises with them?
     
  10. tussery

    tussery Active Member

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    Jul 26, 2008
    Corpus Christi
    It's not like there are not ATF agents at gun shows.
     

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