Gas port size for a 14.5" Colt socom barrel?

In theory, except I don't want to be a sniper target for everyone who will want to argue. And then once we enter into the midlength world for which there is no "standard" it would become a mess.

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Originally Posted by JulyAZ

Since the issue of gas per sizing come up constantly perhaps a sticky should be created with the listing of proper gas port sizing should be for the major barrel lengths. Seems like a new chart is in order.

IG would you be able to make such a chart as a reference for the rest of us?

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Originally Posted by M Sadler

Is it even necessary to try and frame 0.001 as 0.0005 a side?

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For me, yes. I needed to take what the blueprint says and verify that I understood it correctly

Sorry to necro, but does anyone know what the BCM socom barrels measure at? I’ve been considering them lately as I can’t find Colts Socoms in stock from the retailers that I trust.


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Brownell's has them in stock

https://www.brownells.com/rifle-part...prod71337.aspx

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Originally Posted by JulyAZ

Sorry to necro, but does anyone know what the BCM socom barrels measure at? I’ve been considering them lately as I can’t find Colts Socoms in stock from the retailers that I trust.


Sent from my iPhone using Tapatalk Pro

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Not sure on the BCM Barrels, but give Chris at Shark arms a call and he may have the Colt ones. I have ordered numerous times with great services and the best pricing on Colt i have found usually

Is there any data on the Colt CCU mid-length gas port size?

I would like to know as well

CCU mid has been reported as .071”

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Originally Posted by MistWolf

Colt first submitted the XM4 (the M4 prototype) for testing with a .062" gas port and had reliability trouble with one of the types of ammo. They opened up the gas port to .0625 and "it was determined that this gas port diameter performed well in cold temperatures with no carbines failing due to 'lack of power.'"

So in testing, they found a small change made a noticeable difference

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The requirement was that the XM4 works with primarily M855 ammunition but it should not have excessive problems with M193. So much testing was done to ensure that whatever port size was chosen would work with both pressure curves.

Test were performed with 0.062"(or 0.0625"), 0.0635", 0.0645", 0.0655" and 0.0665" gas ports. In order to get reliability results that did not include individual weapons quirks, the gas ports were tested, then reamed to the next larger size and tested again, and they state that the steps were 0.001". The report is a bit confusing as sometimes they state the staring point for reaming the port is 0.062" and other places 0.0625". Then they conclude by stating that a 0.0625" should adequately power the XM4. I believe that that originally it was a standard 1/16 inch diameter drill that was the starting point.

Then the drawing comes out and it states the gas port should be 0.062 +.001/-0".

So, gas ports on new SOCOM barrels should be 0.062" to 0.063" diameter.