Page 1 of 2 12 LastLast
Results 1 to 10 of 12

Thread: Port size for Daniel Defense 5.56 16" S2W mid-length barrel (and a question about it)

  1. #1
    Join Date
    Aug 2006
    Location
    Las Vegas, Nevada
    Posts
    69
    Feedback Score
    0

    Lightbulb Port size for Daniel Defense 5.56 16" S2W mid-length barrel (and a question about it)

    I searched all around here and all around Google but couldn't find this info anywhere. Lots of info other about the 18" was easy to find, but couldn't find a gas port size for that one either. The 16" appears to be far less popular. Because of this, I bought the barrel anyway and I used this as an excuse to pick up a pair of calipers I'd wanted for a while anyway. Edit: turns out it was also a good reason to buy a set of pin gauges.

    The gas port size is 0.072". Hopefully this will be useful to others who search the internet in the future. Edit: There's an attachment with a different measurement using calipers; ignore that photo. That measurement is incorrect as I did it with the wrong tool for the job. The pin gauge measurement below is correct.

    2017-08-01 12-19-15 -0700.jpg

    A question for those who have knowledge of such things: on a scale of picky-about-ammo to over-gassed, where does a 0.072" gas port fall for a mid-length barrel?

    Edited to update info using pin gauges rather than calipers, as I learned from the replies in this thread.
    Attached Images Attached Images
    Last edited by Bryson; 08-01-17 at 15:31. Reason: Additional info for future finders/readers of this thread

  2. #2
    Join Date
    Feb 2012
    Posts
    407
    Feedback Score
    44 (100%)
    Thanks for your work. Gas port sizes are best measured with pin gauges; you probably experienced how hard it is to use calipers. From my notes, DD is using .073" for 16" mid as of June last year. This is on the small side compared to most other companies.

    Sent from my ZTE A2017U using Tapatalk

  3. #3
    Join Date
    Aug 2006
    Location
    Las Vegas, Nevada
    Posts
    69
    Feedback Score
    0
    I really will use any excuse to buy a new tool...guess I need pin gauges now too!

  4. #4
    Join Date
    Nov 2010
    Location
    MI
    Posts
    3,055
    Feedback Score
    21 (100%)
    Very small holes will measure even smaller with the calipers due to the curvature of the hole.

    Pin gauges or the back ends of numbered drill bits should be used instead.
    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

  5. #5
    Join Date
    Jan 2008
    Location
    AZ-Waging jihad against crappy AR's.
    Posts
    24,902
    Feedback Score
    104 (100%)
    The only way to get a good solid number is with pin gages.



    Owner/Instructor at Semper Paratus Arms

    Facebook: https://www.facebook.com/SemperParatusArms/

    Semper Paratus Arms AR15 Armorer Course http://www.semperparatusarms.com/cou...-registration/

    M4C Misc. Training and Course Announcements- http://www.m4carbine.net/forumdisplay.php?f=141

    Master Armorer/R&D at SIONICS Weapon Systems- http://sionicsweaponsystems.com

  6. #6
    Join Date
    Aug 2006
    Location
    Las Vegas, Nevada
    Posts
    69
    Feedback Score
    0
    I got a set of pin gauges and measured the port at 0.072". Tried 0.073" and it was definitely a no-go; not just snug, but won't fit at all.

    2017-08-01 12-19-15 -0700.jpg

    I have updated my original post so future finders of this thread won't get bad info if they skip the replies.

  7. #7
    Join Date
    Nov 2010
    Location
    MI
    Posts
    3,055
    Feedback Score
    21 (100%)
    That is a conservative size.

    How does it run?
    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

  8. #8
    Join Date
    Sep 2007
    Posts
    2,954
    Feedback Score
    22 (100%)
    Quote Originally Posted by Clint View Post
    That is a conservative size.

    How does it run?
    Yet on their other barrels, their ports larger than normal https://docs.google.com/spreadsheets...#gid=766121382

    DD seems to make the only 14.5" carbine length CHF pencil barrel but their gas port size of 0.067" is a bit too large for my taste. Will your gas port insert work with a .625 DD FSB? That might be my only option get that kind of barrel with a mil-spec gas port.

  9. #9
    Join Date
    Jan 2013
    Posts
    155
    Feedback Score
    0
    Most experts here agree that .076 is the ideal port size for 16" mid. No idea why DD port size is smaller. Then again there are a lot of DD owners out there and theirs seem to be running fine, but you might run into some issues if you used heavier buffer (like H2).

    EDIT to add: It seems like DD barrels are all over the place with port sizes. Their MK18 used to have .080 port and recently reduced to .072 (mil-spec size). Some of their carbine barrels are .067 instead of standard .063
    Last edited by Serious Account; 08-01-17 at 18:08.

  10. #10
    Join Date
    Nov 2010
    Location
    MI
    Posts
    3,055
    Feedback Score
    21 (100%)
    Quote Originally Posted by vicious_cb View Post
    Yet on their other barrels, their ports larger than normal https://docs.google.com/spreadsheets...#gid=766121382

    DD seems to make the only 14.5" carbine length CHF pencil barrel but their gas port size of 0.067" is a bit too large for my taste. Will your gas port insert work with a .625 DD FSB? That might be my only option get that kind of barrel with a mil-spec gas port.
    It is interesting to see such variations in gas drive from the same mfg.

    They do seem to be toning down the mk18s too, so perhaps it's a new thing.

    Yes, of course, the insert works in any mill spec FSB.
    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

Page 1 of 2 12 LastLast

Bookmarks

Posting Permissions

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