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Thread: Barrel Question for a new project ;17" rifle gas barrel

  1. #21
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    Quote Originally Posted by jmart View Post
    I believe they do. Check out their shop services section on their website. I know they used to offer a service of gas lort relocation which involved welding up existing port and drilling a new one, and I'm assuming included everything needed to do this properly (chamfering, etc.). You'll just have to check with them if they still provide the drilling service and if they have a recommended gas port size for a non-std barrel length for a gas port that would remain at the rifle-length location.

    Since you're using an adjustable gas port as well, that ultimately will constrain how much gas enters the DI system, but discussion up to now seems to be centered on delivering enough gas to the adj gas block which will be barrel gas port diameter sensitive. From reading this thread, and given the shorter dwell, I suspected that the port would have to be enlarged a tad if starting with a 20" barrel.
    I think you're right about the GP size.

    Iron man 8 gave an email contact for a guy at ADCO who had treated him well. I think I'm gonna use the same guy for my questions.

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  2. #22
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    Lancer sells some 17" ARs with rifle gas systems.

    I haven't handled one or ready any reviews. But they are out there.

  3. #23
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    Okay, I'm looking at the Criterion 18" hybrid profile , CL'd, with rifle gas.

    http://criterionbarrels.com/ProductP...15Listing.html

    I'm going to call them this week to see if they can cut/thread at a 17" length in-house for some additional cost. I'll advise. If they can dot hat work in-house, that obviates the need for the barrel to go to ADCO for the time being.

  4. #24
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    Quote Originally Posted by BufordTJustice View Post
    So it's gonna be more of a gas port issue. Maybe I can have ADCO drill the gas port out to .100 since I can constrict the supply but not increase it. What do you think?

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    It may well be. I seem to remember someone that could thread gas ports for an insert to reduce port size. It might be a way to experiment with port sizes.

    If it were me doing this project, one thing I'd consider (since it's all custom work anyway) is adjust the gas length to fit the 17" barrel. It does mean a custom fit gas tube, but it shouldn't be hard to have made (or a gas block made with a longer snout so a middy length tube could be used).

    At any rate, I'd specify a smaller gas port and shoot it, opening it up a little at a time until the rifle functioned correctly, then maybe open it just a tad bit more to be sure. I'd only use the adjustable gas block to fine tune the gas system, especially if the gas block uses one of those fragile hex set screws like the JP. Save the pinning of the gas block until after getting the gas port right (have it drilled and just use the set screws)
    Last edited by MistWolf; 11-18-12 at 23:57.
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  5. #25
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    Quote Originally Posted by MistWolf View Post
    It may well be. I seem to remember someone that could thread gas ports for an insert to reduce port size. It might be a way to experiment with port sizes.

    If it were me doing this project, one thing I'd consider (since it's all custom work anyway) is adjust the gas length to fit the 17" barrel. It does mean a custom fit gas tube, but it shouldn't be hard to have made (or a gas block made with a longer snout so a middy length tube could be used).

    At any rate, I'd specify a smaller gas port and shoot it, opening it up a little at a time until the rifle functioned correctly, then maybe open it just a tad bit more to be sure. I'd only use the adjustable gas block to fine tune the gas system, especially if the gas block uses one of those fragile hex set screws like the JP. Save the pinning of the gas block until after getting the gas port right (have it drilled and just use the set screws)
    I'm tracking.

    The Syrac GB looks to be pretty sturdy for an adj unit.....leaving the GP small and opening up (if required) may be better, if more time consuming. I remember reading somewhere about that threaded GP....but IIRC the port could not be used with no insert, since it would erode the threads.

    If I were a company prepping for production, that would be worth it.

    I like the allure of using a rifle gas tube. It's kinda like seeing an authentic 427 Shelby Cobra S/C w/ some HID headlights and a straight cut gearbox. It's new mixed with old.

    AND, I can use Colt gas tubes which are a known-quality component.

    I'm excited to talk with Criterion about this.

    Also, the TRX Alpha rail in 15" length seems to be a frontrunner for value/quality right now. I would actually prefer a KAC URX 3.1, but those still leave the GB exposed and that's a no-go for this project.

    If I brace the gun against a 4x4" post during a course of fire, I do NOT want to have to worry about pushing the GB out of alignment. I'll sacrifice some speed of access to the GB adjustment detent and screw for some security.

    I also may look at the Geissele Rail, depending on weight.

    Keep the good advice and thoughts coming....

  6. #26
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    What would be really cool is dropping a Ford 5.8L supercharged, aluminum block V8 with 650 horsepower and 600 lb.-ft. of torque into a 2200 lbs Cobra chassis

    ...and now you know how expensive my hobbies would be if I had real money
    ..........................and
    .................................this
    ........................................is
    ............................................way
    ..................................................off
    ......................................................topic,
    ...............................................................isn't it?
    INSIDE PLAN OF BOX
    1. ROAD-RUNNER LIFTS GLASS OF WATER- PULLING UP MATCH
    2. MATCH SCRATCHES ON MATCH-BOX
    3. MATCH LIGHTS FUSE TO TNT
    4. BOOM!
    5. HA-HA!!

    -WILE E. COYOTE, AUTHOR OF "EVERYTHING I NEEDED TO KNOW IN LIFE, I LEARNED FROM GOLDBERG & MURPHY"

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  7. #27
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    I'd just have the port cut by a pro and not work about the rest. My 17" small port shoots Wolf in a pinch. Dirty and cold it probably wouldn't. Is that a criteria for you?

  8. #28
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    Have you thought about calling White Oak or Compass Lake Engineering about a custom length? They both make some very accurate barrels. They could possibly drill a custom port size for you. I'm not positive that they would do it, but they used to turn custom profiles.
    Last edited by mtdawg169; 11-19-12 at 04:14.

  9. #29
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    I've been considering the same exact thing. I'm tagging this just so I can easily follow along your progress and see how it works.

  10. #30
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    Fulton sells a cut down A1 barrel, 16" rifle gas

    http://www.fulton-armory.com/barrelu...romelined.aspx

    Twist rate is only acceptible for 55gr and less but I've heard they do run. Not sure what they opened the port to, assuming they did.

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