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11/22/2017 10:05:29 PM
Posted: 9/5/2004 1:28:28 PM EST
If I want to convert a 16" AR barrel to a 14.5" with a long muzzle brake to make it 16" do I have to open up the gas port on the barrel? Seems like I read somewhere if you dont open the port up the bolt carrier wont cycle right. Any suggestions?
Link Posted: 9/6/2004 9:15:22 AM EST

You might try changing title to include "Gas port size question"
Link Posted: 9/6/2004 1:16:24 PM EST
Should be fine as is. Shoot it first.
Link Posted: 9/6/2004 4:38:10 PM EST

Originally Posted By SBR7_11:
Should be fine as is. Shoot it first.

Guess that wouldnt hurt.
Link Posted: 9/6/2004 4:55:12 PM EST
Link Posted: 9/6/2004 5:00:13 PM EST
I just (like last week) lopped 1.5" off of a Bushmaster 16" barrel.

Pinned a Phantom on it and took it out to sight it in. Without touching the gas port, it seems to work fine. I only fired about 20-30 rounds through it, but so far so good.

Link Posted: 9/7/2004 5:15:48 AM EST
Steve at ADCO cut a RRA barrel down to 14.5 and installed a phantom for me, and I have not had any problems yet, have put about 200 rounds thru it.
Link Posted: 9/7/2004 6:10:53 AM EST
same size hole.....
Link Posted: 9/7/2004 6:38:31 AM EST
So when is there a need for different sized holes?
Carbine vs mid/rifle length?
Is there a SPEC size hole for the various gas port placements and barrel sizes?
Link Posted: 9/7/2004 7:58:25 AM EST
It should be the same size hole. There is a reference on the Maryland AR-15 site that gives gas port diameter ranges for different barrel length and diameters:


Scroll about halfway down and look for the table.
Link Posted: 9/7/2004 2:41:20 PM EST
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