survivalshop Posted February 6, 2014 Report Share Posted February 6, 2014 (edited) We can post the info here or a Sticky thread on our barrels we install or replace or when we have them off the upper for work . Note the particular's of the barrel, who made it , what port size you have . It shouldn't take too long to get some good data , for reference . I have my 16" barrel off right now & will try to get as good of a reading as I can .Robo & 98 , I'm sure has some data to share. Fulton Armory , Krieger Criterion ,16"HB , 0.936 " gas block , rifle length gas system , aprox. port diameter - ? This way ,we are not stepping on toes or giving out secrets or twisting any arms , so to speak. Edited February 6, 2014 by survivalshop Quote Link to comment Share on other sites More sharing options...
survivalshop Posted February 6, 2014 Report Share Posted February 6, 2014 (edited) Fulton Armory , 16" HB ,0.936" gas block seat, rifle length gas system , port diameter -0.1095" . A 7/64 drill bit fit right in the port ,took a very small amount of twisting to get bits shank in there ,but fits perfect , so I measured the drill bit with a Micrometer & digital caliper . Edited February 6, 2014 by survivalshop Quote Link to comment Share on other sites More sharing options...
Dane Armory Posted February 6, 2014 Report Share Posted February 6, 2014 SORRY I did not mean to come off like a DICK !! Here are some basic numbers : For 308 guns Rifle length gas system .088" factory spec .089 "another mfg .087" thur .095" several other companies .094" thur .096" two really high end barrel makers .1065" max size on a very ill gun Carbine gas system .074" .076" also M14 port size .079" thur .0805" .0835" thur .084" 16 inch barrel As with everything like this start at the smallest size and work up One drill bit size at a time. Number #47 bit or a#43 bit will put you in the ball park. Remeber gas port holes erode with use ! Warning use data with caution ; I did not use any company names ! These are starting points. If you go too big an adjustable gas block will be your "Band ade" fix. The max size of the gas tube is about .110" . Did I mention USE At YOUR OWN RISK . Get your own Data ! Quote Link to comment Share on other sites More sharing options...
survivalshop Posted February 6, 2014 Report Share Posted February 6, 2014 (edited) SORRY I did not mean to come off like a DICK !! You didn't IMO , I & I believe others understand . .1065" max size on a very ill gun Are you saying I have a "ill gun " ? <laughs> Is there a doctor in the house . This rifle has not had enough rounds to make even remotely " ill " , These FA barrels probably do not conform to normal port sizes of a rifle length gas system . This 16" rifle is not over gassed in any way IMO This is why I would like to start another thread on port sizes, so we can see what is out there , just for info & trouble shooting purposes . Not sure where I want or should start a new thread on this subject . Edited February 6, 2014 by survivalshop Quote Link to comment Share on other sites More sharing options...
Dane Armory Posted February 6, 2014 Report Share Posted February 6, 2014 You answered your own question ... 16 inch gun with a a rifle lenght gas system. From the gas port to the muzzle is blank inches, much shorter than a regular rifle gas lenght barrel of 20 inches to 24 inches. As the bullet passes the gas port hole it starts its cycle to feed the bolt carrier key with gas which propels the carrier in reverse. The lenght of barrel which is between the gas port and the muzzle is shorter so the gas port hole must be larger to provide enough volume of gas to operate the bolt carrier's weight. Adjustable weight on the carrier , adjustable gas blocks , different weights of buffers all fix a bad port size. If the port size is right the ejection of brass is at 3 O'clock and we would not have to fix anything. SS the last part of that rambling statement was not for you but just info. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted February 6, 2014 Report Share Posted February 6, 2014 I Emailed FA , any way, just for shits & giggles , to see what they have to say about it . & I don't think you ramble ! <thumbsup> Quote Link to comment Share on other sites More sharing options...
1911popo Posted February 7, 2014 Author Report Share Posted February 7, 2014 Ok I'll play 20" AR 10 T HB .096 diameter 16" 5.56 Noveske HB .084 diameter 24" 5.56 Krieger HB .089 diameter Quote Link to comment Share on other sites More sharing options...
htbde Posted February 7, 2014 Report Share Posted February 7, 2014 I suggest change the oil(clean it) and re fill with new oil and lots of it. Quote Link to comment Share on other sites More sharing options...
shibiwan Posted February 7, 2014 Report Share Posted February 7, 2014 (edited) I suggest change the oil(clean it) and re fill with new oil and lots of it. An oil change? You're making it sound like it's a vehicle. Perhaps a short cycle like this: Edited February 7, 2014 by shibiwan Quote Link to comment Share on other sites More sharing options...
htbde Posted February 7, 2014 Report Share Posted February 7, 2014 Mine, since it was new required cleans and copious amount of oil. Once it broke in, it fired like a runaway 60. Quote Link to comment Share on other sites More sharing options...
MikedaddyH Posted September 14, 2015 Report Share Posted September 14, 2015 JT this is the thread with gas port sizes. Quote Link to comment Share on other sites More sharing options...
GRA Posted September 19, 2015 Report Share Posted September 19, 2015 An oil change? You're making it sound like it's a vehicle. Perhaps a short cycle like this:This man has issues. LOL Quote Link to comment Share on other sites More sharing options...
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