1:00 ejection & Short stroking ?

**Inkslinger** · 04-04-22, 17:12

Originally Posted by JoeBobJoe

I don't see any signs of leaking gas. I even put paper around gas tube where it goes into gas block, the paper doesn't move or get tore up. The Carrier & upper are clean looking, I ran another carrier & ran that carrier in other gun. I pulled my gas block (pinned from factory)had perfect alignment. I'm thinking about opening the gas port, since I got it apart. Crazy, but It's not reliable, I value reliability over everything. What's your thoughts on opening gas port a hair. My son has pinned front sights & gas blocks so I got some knowledge to help me.

Take it to someone who has pin gages before you start drilling things. Like I said above, I would try new springs in the problem mags before you start removing metal.

**HKGuns** · 04-04-22, 17:32

Yeah, I would definitely measure the gas port size before doing any drilling.

You can’t really do that over.

**markm** · 04-04-22, 17:46

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.

**JoeBobJoe** · 04-05-22, 04:29

Originally Posted by markm

It sounds like it, but under gassing would be almost unheard of with most guns being over gassed. Any signs of leakage around the gas block or gas key?

Any other ammo you can try?

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.

**JoeBobJoe** · 04-05-22, 04:37

Originally Posted by Inkslinger

Take it to someone who has pin gages before you start drilling things. Like I said above, I would try new springs in the problem mags before you start removing metal.

The mags are newer like 150 to 300 rounds through them & have run in 3 other longer & shorter AR's. IDK it's now a obsession to get it to run reliable, & a father & son quest, lol. My son is ready to drill. I'm letting him it's only a barrel.
Thanks for the help.

**tech3** · 04-05-22, 07:58

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?

**markm** · 04-05-22, 08:48

Originally Posted by JoeBobJoe

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.

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.

**JoeBobJoe** · 04-05-22, 16:48

Originally Posted by markm

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.

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.

**markm** · 04-05-22, 16:54

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.

**HKGuns** · 04-05-22, 17:24

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