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Thread: 20" Rifle gas port size

  1. #1
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    20" Rifle gas port size

    What is the TDP spec for gas port size for 20" Rifle gas barrel?

    A couple of mine measure in the .090 to .093 range, just wondering what is default.

    Thanks

  2. #2
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    Should be .093



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  3. #3
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    Quote Originally Posted by BFS View Post
    A couple of mine measure in the .090 to .093 range, just wondering what is default.
    20" Rifles should run just fine with those sizes.
    Black River Tactical
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    Thank you for the quick responses- I have a few follow up questions.

    I thinking of building a lightweight (not ULTRAlight- normal lightweight) rifle mostly for hunting Mule Deer and Whitetail (Im not interested in getting comments for using 5.56 for hunting big game- I know there are better calibers out there but Im not interested- I hunt with 5.56, it is what it is).

    I like the 20" platform for hunting- its quieter and squeezes out a tiny bit better velocity and distance out of 5.56, and generally has less recoil than my 16" guns which helps keep my glass on the animal for running shots.

    I'm particularly attracted to the Faxon 20" GUNNER profile barrel, looks very light, decent quality, and resonably priced. Thinking I will put this on an A5 lower with minimal-minded furniture.

    That barrel has a .081 gas port- seems quite small to me. Im thinking with a port that small I could use the lightest A5 buffer available, and perhaps even use a commercial "AR15" style cutout carrier to save OZ.

    So my questions-

    1. Are the Faxon barrels GTG? Accurate? Sufficient hunting accuracy would be a dependable 12" group @ 300yds- (minute-of-deer) with a COLD barrel (always below freezing, sometimes even below 0F) using my standard hunting ammo- Federal Fusion .223 (Not the MSR version- the bolt gun version is loaded a bit hotter).

    2. Would a AR15 "semi auto" style carrier on a H0 A5 buffer be a low recoil gun with that .081 gas port?

    3. Does anybody make a truly squared away AR15 style carrier?

    Thanks in advance

  5. #5
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    Quote Originally Posted by BFS View Post
    Thank you for the quick responses- I have a few follow up questions.

    I thinking of building a lightweight (not ULTRAlight- normal lightweight) rifle mostly for hunting Mule Deer and Whitetail (Im not interested in getting comments for using 5.56 for hunting big game- I know there are better calibers out there but Im not interested- I hunt with 5.56, it is what it is).

    I like the 20" platform for hunting- its quieter and squeezes out a tiny bit better velocity and distance out of 5.56, and generally has less recoil than my 16" guns which helps keep my glass on the animal for running shots.

    I'm particularly attracted to the Faxon 20" GUNNER profile barrel, looks very light, decent quality, and resonably priced. Thinking I will put this on an A5 lower with minimal-minded furniture.

    That barrel has a .081 gas port- seems quite small to me. Im thinking with a port that small I could use the lightest A5 buffer available, and perhaps even use a commercial "AR15" style cutout carrier to save OZ.

    So my questions-

    1. Are the Faxon barrels GTG? Accurate? Sufficient hunting accuracy would be a dependable 12" group @ 300yds- (minute-of-deer) with a COLD barrel (always below freezing, sometimes even below 0F) using my standard hunting ammo- Federal Fusion .223 (Not the MSR version- the bolt gun version is loaded a bit hotter).

    2. Would a AR15 "semi auto" style carrier on a H0 A5 buffer be a low recoil gun with that .081 gas port?

    3. Does anybody make a truly squared away AR15 style carrier?

    Thanks in advance
    I use the Faxon 18" gunner with an adjustable gas block, Vltor A5H4 buffer , and Tubbs AR10 flat wire spring, with LMT e-carrier. The gas block is just over 1/3 restricted.

    I shot five 3 round, 3 shot groups this past Monday using an Aimpoint micro T1 4 moa and federal Brown box XM193. I wasn't going for accuracy as much as I was refining my zero at 100 yards.

    Recoil is virtually non existent. Gun is 6.95 pounds with a surefire 2xCR123 light, sling mounts, backup irons, but no mag.

    That barrel will shoot pretty decently as long as you don't heat it up too much.
    "That thing looks about as enjoyable as a bowl of exploding dicks." - Magic_Salad0892

    "The body cannot go where the mind has not already been."

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    Yes, good info- Ive been following your thread on the Faxon 18"

  7. #7
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    Quote Originally Posted by BFS View Post
    What is the TDP spec for gas port size for 20" Rifle gas barrel?

    A couple of mine measure in the .090 to .093 range, just wondering what is default.

    Thanks
    The drawing shows:

    .092 +.001 thru this side only, break external sharp edge .015" max, no internal burr permitted.

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