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survivalshop

Barrel Gas Port Size,308/338/260/243 etc.

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  I'm starting a thread on this in hopes the STAFF here will make it Pinned . Only info needed here is if you know your Barrels Port size , post it here , with Manufacturer , Gas system length  & Barrel length & if you had to make any changes to it to make it work if you had issues.

 

  Kreiger Criterion  308 ,16" HB  , Rifle Gas system  ------   0.1095 "

  Sharps , 25-45 Sharps , 20" LT , Rifle gas system ----       0.09375"

Here is some info from Tactical Machining

 

AR-15 GAS PORT SIZES

Disclaimer: These are lists of compiled information from multiple sources. While we make our best effort to test and produce these should be considered for reference only. Any time you start messing with the gas port on your rifle you run the risk of destroying the barrel or causing it to be over gassed. It is much better to slowly work your way up to what you would be happy with.

AR-15 Platform 5.56mm
20" rifle 5.56   0.0935
20" rifle 5.56   0.096
20" rifle 5.56   0.098
16" mid 5.56   0.078
16" mid 5.56   0.081
16" car 5.56   0.0625
16" car 5.56   0.065
16" car 5.56   0.07
14.5" car 5.56   0.067
14.5" car 5.56   0.086
11.5" car 5.56   0.081
11.5" car 5.56   0.089
24" rifle 5.56   0.089
AR-15 Platform 7.62x39mm Conversion
20" rifle 7.62x39   0.12
20" rifle 7.62x39   0.125
16" car 7.62x39   0.078
16" car 7.62x39   0.081
16" car 7.62x39   0.0938
DPMS LR-308 Style Rifle
18" rifle 0.308   0.0960
18" car 0.308   0.0635
16" mid 0.308   0.078
16" mid 0.308   0.081
16" car 0.308   0.07
16" car 0.308   0.073
16" car 0.308   0.076
20" rifle 0.308   0.0935
20" rifle 0.308   0.096
AR-15 Platform 300 BLK Conversion Subsonic Ammo
16" car 300 BLK UNSUPRESSED 0.12
16" car 300 BLK UNSUPRESSED 0.125
16"  car 300 BLK SUPRESSED 0.106
16"  car 300 BLK SUPRESSED 0.11
16" pistol 300 BLK UNSUPRESSED 0.067
16" pistol 300 BLK SUPPRESSED 0.086
9.5" pistol 300 BLK UNSUPRESSED 0.093
9.5" pistol 300 BLK SUPPRESSED 0.093
8.1" pistol 300 BLK UNSUPRESSED 0.104
8.1" pistol 300 BLK UNSUPRESSED 0.12
8.1" pistol 300 BLK SUPRESSED 0.086
8.1" pistol 300 BLK SUPRESSED 0.093
         
         
AR-15 Platform 300 BLK Conversion Supersonic Ammo
16" pistol 300 BLK UNSUPRESSED 0.0625
16" pistol 300 BLK SUPPRESSED 0.059
16" car 300 BLK UNSUPRESSED 0.099
16" car 300 BLK SUPPRESSED 0.093
9.5" pistol 300 BLK UNSUPRESSED 0.073
9.5" pistol 300 BLK SUPPRESSED 0.067
8.1" pistol 300 BLK UNSUPRESSED 0.076
8.1"  pistol 300 BLK SUPPRESSED

0.067

The 300 Blackout data has been compiled from Micro MOA

Edited by survivalshop

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Armalite AR-10 barrel, 13.5" OAL, midlength gas system, gas port diameter 0.081".

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16 inch barrels of many different makes and a lonely 18 inch barrel all are mid length all at .081         Wash

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5.56 info here-

Ballistic Advantage .223 Wylde SPR barrel: 18" .223 Wylde SPR Stainless Steel Rifle Length AR 15 Barrel w/ Ops 12, Premium Series, 1:8" twist

Gas port diameter: 0.095"

 

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From 308KIKI

FWIW, dunno if you guys want to add this to the "gas port dia thread",

 

AR 243, 20" barrel, Rifle gas system, gas port dia .095"

Works a treat


 

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Another 6.5 Grendel barrel spec:

Faxon Firearms 6.5 Grendel gas port info: Match Series- 18" Gunner, 6.5 Grendel, MIDLENGTH GAS SYSTEM, 416-R, 5R, Nitride, Nickel Teflon Extension - Gas Port diameter = 0.077".

Edited by 98Z5V

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PSA 18" Stainless .308 barrel, "midlength" gas system.  0.073" fits, 0.076" does not fit.

This gas port is too small.

Edited by 98Z5V

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Found the thread with our original gas port data:

 

Found it by looking for this chart, that I knew I'd seen here.  .308 min and max gas port sizes, by barrel length, from one specific reputable manufacturer:

GAS PORT DIAMETER AND LOCATION.jpg

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Rainier Arms Select .308 barrel, stainless, 18", true AR15 midlength gas system.  Gas port diameter 0.081".

Edited by 98Z5V

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.308 win 16 inch rifle gas(AR15rifle), X-Caliber barrel ended up at .1005", runs everything there.

Edit; .750" diameter at the gas block.

Edited by jtallen83

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.260 Remington info:

Wilson Combat .260 Remington Tactical Hunter barrel, 20"  rifle gas,1:8" twist.  Recessed 11-degree target crown.  416R stainless.  Gas port diameter is 0.071".  Weight is 1205 grams/42.5 oz/2.65lbs.

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Wilson Combat .338 Federal  

Gas Port Size  .0705" by my chinese calipers on my chinese drill bits.............
 Gas Block Seat     .750" Diameter 
 Gas System     Intermediate-Length (13.25") the tube delivered with the barrel was actually 13 3/16" by my Stanley tape.
 Length     14.7"
 Rifling     1:10, RH, Six Groove, Precision Button Rifling
 

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22 hours ago, jtallen83 said:

 Intermediate-Length (13.25") the tube delivered with the barrel was actually 13 3/16" by my Stanley tape.

Very interesting, brother...   :thumbup:

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Ballistic Advantage Modern Series, Mk12 profile, 5.56 chamber, 1:7" twist.

18" 5.56 SPR Rifle Length AR 15 Barrel w/ Ops 12, Modern Series

This one:  https://www.ballisticadvantage.com/18-inch-556-spr-rifle-cmv-modern-barrel-ops12.html

Gas port diameter is 0.095", 18" 5.56 barrel, rifle gas. 

This is very close to what an 18" rifle gas .308 Win barrel needs to be. Here's the barrel referenced:

18in_5.56_spr_modern_1.jpg

 

 

 

 

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