Close
Results 1 to 9 of 9
  1. #1
    Ryobi Robb Robb's Avatar
    Join Date
    Jan 2007
    Location
    Thornton, CO
    Posts
    1,224

    Default 10.3" gas port size please

    Long story is the kid got his tax stamp for a SBR, so we're having a COLT 16" barrel cut down to 10.3".
    This is for 5.56/223, not suppressed AT THIS TIME. A can MAY be in the future depending on how life goes. The barrel will retain the fixed Colt factory front sight.
    Son does not care to run an adjustable gas block, he likes the look of the standard front sight.
    Ive read the diameters for gas ports run from .070 with .083 being used by Daniel Defense and .093 by Colt.

    Again, Someday we may want to get a can, but for now it will be shot unsuppressed.

    The smith I took it to asked me what gas port I wanted, didn't know what to say. He recommended .0925 (I think that's what he said).

    What would you folks recommend?
    Thanks,
    Robb

  2. #2
    Worlds Shortest Tall Guy kwando's Avatar
    Join Date
    Nov 2005
    Location
    Elizabeth, Colorado
    Posts
    3,675
    "An armed society is a polite society when a man may have to back his last words with gunplay."

    My Feedback

  3. #3
    Ryobi Robb Robb's Avatar
    Join Date
    Jan 2007
    Location
    Thornton, CO
    Posts
    1,224

    Default

    Okay, I read .093 earlier, I guess we'll go with .070.
    Last edited by Robb; 11-02-2016 at 17:07.

  4. #4

    Default

    .076, and get an adjustable gas block. .076 is a bit over-gassed with a standard block but will run most ammo. DD's "mk18" ports are .08- something, and they're a bit hot in my opinion. .069-.070 works great with a can, but not always w/out. May want to run an H1 or an H2 buffer

  5. #5
    High Power Shooter
    Join Date
    Mar 2011
    Location
    westminster
    Posts
    764

    Default

    I have a factory non-cut down DD 10.3 barrel .070 port, their mk12 gas block, Wolff XP spring and Spikes T2 buffer. Works every time suppressed or non-suppressed.
    Until Geissele SD-3G, shooting PMC bronze 223, trigger won't reset, Perfecta and all 5.56 no problem.

  6. #6
    Ryobi Robb Robb's Avatar
    Join Date
    Jan 2007
    Location
    Thornton, CO
    Posts
    1,224

    Default

    We went with a .070, I'll keep the buffer weights in mind in case we run into relialibility issues

  7. #7

    Default

    Quote Originally Posted by Robb View Post
    We went with a .070, I'll keep the buffer weights in mind in case we run into relialibility issues
    .070, H2 buffer, Tubbs flat wire spring.
    or
    .070, H buffer, Tubbs spring, adjustable gas key BCG
    or
    .070, carbine or H buffer, Tubbs spring, adjustable gas block

    .070 is a little bigger than what it should be, but with such a short dwell time on a 10.5" barrel it needs more punch up front to make it consistently work with anemic ammo (PMC 223) all the way to 5.56 ammo. Every time I see someone go too small on the gas port on a 10.3/10.5", it becomes a short stroke nightmare. LMT's are notorious for this. Have them stay in this size range initially. If needed, it can always have the A-fram removed and the port honed out a tad more to get the timing right. Can't put metal back in that gas port though.
    Mom's comin' 'round to put it back the way it ought to be.

    Anyone that thinks war is good is ignorant. Anyone that thinks war isn't needed is stupid.

  8. #8
    Stircrazy Jer jerrymrc's Avatar
    Join Date
    Jan 2004
    Location
    Colorado Springs
    Posts
    8,166

    Default

    Quote Originally Posted by SA Friday View Post
    Can't put metal back in that gas port though.
    This. Always can go bigger, little more difficult to go smaller.
    I see you running, tell me what your running from

    Nobody's coming, what ya do that was so wrong.

  9. #9
    The "Godfather" of COAR Great-Kazoo's Avatar
    Join Date
    Sep 2003
    Location
    Washboard Alley, AZ.
    Posts
    48,076

    Default

    Quote Originally Posted by jerrymrc View Post
    This. Always can go bigger, little more difficult to go smaller.
    Wait till you hit 60+
    The Great Kazoo's Feedback

    "when you're happy you enjoy the melody but, when you're broken you understand the lyrics".

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •