Yeah, I would definitely measure the gas port size before doing any drilling.
You can’t really do that over.
Agree on reaming the port being the LAST option. If the Port is .076" or greater, that isn't the problem.
I have this large needle that I mark with a sharpie. I poke it into the port, and use calipers to measure where it stops inside the port. Not perfect, but it gets me within 1 or 2 thousandths which is good enough.
"What would a $2,000 Geissele Super Duty do that a $500 PSA door buster on Black Friday couldn't do?" - Stopsign32v
The gas port was .063..... I opened it up. I won't say how much because that will be a can of worms, but let me say .080 is not large as .093 is common even on mid length gas systems. The spent brass was falling out 3 feet, I think the bolt was hitting the cases as it was closing shooting them forward at 1:30 but with a lighter buffer I got them to 3:00 still only about 3 feet with intermittent stoppages.
I opened it up a bit & but still not much change. Now going wide open. I'll post tomorrow when I give it a go. Thanks for the help.
Last edited by JoeBobJoe; 04-05-22 at 04:50.
God, Family, Freedom.
God, Family, Freedom.
This might be a Dum question, but have you checked the tension on the ejector spring
taken it apart and cleaned the spring and ejector and lube them?
Wow. .063" on a 16" middy??? That's lean. For me .076" one a 14.5" middy is a touch lean to where I drop the buffer weight down to H buffer from H2, and it's perfect.
I have a .080" 14.5" middy that's gassed where you'd probably really want it for adverse conditions reliability.
"What would a $2,000 Geissele Super Duty do that a $500 PSA door buster on Black Friday couldn't do?" - Stopsign32v
I opened the gas port to .075 no improvement so I finally opened to .093 now it's ejecting just a bit further now about 5 feet & closer to 3:00 with the T2 buffer back in. I'm gonna run a few mags before I declare it stopped the "short stroking" for sure, but it's not running sluggish anymore. I wasn't gonna say how much I opened it up to because of all the flack larger gas port sizes get, but figured someone else could benefit from my information. I opened the port as a last resort after many rounds of testing & trying different less permanent solutions, it worked for me & my wants & needs; to make my particular AR reliable.
I am buy no means recommending this is a solution for every AR or everyone. Thanks again to everyone, I appreciated the help & suggestions.
If any trouble comes up I'll let you all know.
Last edited by JoeBobJoe; 04-05-22 at 16:57.
That's interesting. Based on my middys/ports that sounds massive, but if it works, that's good. Update us if you get some more time on the gun.
"What would a $2,000 Geissele Super Duty do that a $500 PSA door buster on Black Friday couldn't do?" - Stopsign32v
I got a new barrel in today.
416R Stainless - Wilson Combat - 16" - 556 Nato - 1/8 - Midlength. It measured at exactly .078 as in my experience, it falls into the .076/78 range as most of my other 16" midlength 556 barrels.
.063 is indeed on the lean side, but .093 sounds Yuge and I suspect there may be more than one issue if you had to open it up that much.
Is there a barrel length / gas length / optimum gas port size chart anywhere?
ETA: I looked a bit and found these, not sure if 100% accurate. I was able to find Colt uses .063 for a 16" Carbine length gas system so yours may have been a mistake.
GAS PORT SIZES
Last edited by HKGuns; 04-05-22 at 18:16.
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