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AR15.COM
7/2/2026 12:31:26 PM EDT
I see that it says that the gas pocket BCG shouldn’t be used with .300 Blackout because it may cause cycling issues, but I’m trying to understand why.  Isn’t the same amount of gas going to the bolt carrier chamber, with the main difference from a conventional BC being that it vent inside of the receiver instead of out the ejection port?  Where is more gas being bleed off from cycling the action?  I’m mainly speaking about the mil-spec version of the gas pocket BCG, if that makes a difference.  TIA.
7/3/2026 8:44:44 PM EDT
[#1]
The .300BLK subsonic is barely cycling with certain suppressors, so the gas pocket BCG is just one more variable.  I've heard that with the adjustable gas block, the gas pocket BCG makes the gun not run properly in subsonic.  

The block leaks a tiny bit of gas, and the gas pocket BCG might push the BCG into the side of the receiver also dropping a tiny amount of bolt speed?  The two parts are not recommended to be used together in 300BLK subsonic.

We also did not derive benefit from running the gas pocket BCG in gas systems shorter than carbine, so there is no reason to use it on a pistol gas blackout.
Austin, Managing Partner - www.GriffinArmament.com

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