PSA 18" upper short stroking. Anyone else?

[sharpshooter33]

Ok reading the reviews...after I purchased my 18" PSA upper.
Looks like they may have an issue with short stroking on the rifle length gas system in their 18" barrels.
Looks like someone opened the gas port to .101 from .077 and had no further problems.
This reminds me of an issue I had with a Faxon 7.5" barrel in 300BO short stroking subsonic rounds. Faxon opened up the gas port for me to .101 and it worked flawlessly.

Has anyone else here had problems with PSA 18" uppers in 6.5G?

My 12" PSA works just fine.

Don't want to pull it apart if PSA is going to fix it anyway. But it would make since that 18" with rifle length gas system would need a bigger port size.

Any thoughts?

[Jakegsxr11]

My 18" RLGS Brux barrel has a 0.094" port and runs great.

[CaptnC]

Try a little lube on your buffer. A good friend who uses AR's in some of his three guns stuff. Had one short stroking and he said a little lube put it back on track...

Be something simple to try before doing a tear down.

[Bill257]

Had same issue.... I cleaned it up prior to shooting and oiled as normal. Had failure to feed several times. Ran 30 or so rounds through it after another cleaning and ensuring gas port was aligned with gas block still had FTF every 2 to 4 rounds. (flash hider was really tight, but gas block was almost loose enough to pull off by hand) Was ready to put on a new gas block as I felt that is where the problems was, but decided to let PSA work with it first. PSA gladly sent shipping label and returned it quickly.
Back at the range, same result.
Rather than work on it I returned it to PSA for refund. I think the gas port is too small and or the gas block had an issue and pretty sure enlarging the gas port and putting on the new block would have been the route I would have taken had PSA not agreed to take it back.
good luck

[98Z]

Ok reading the reviews...after I purchased my 18" PSA upper.
Looks like they may have an issue with short stroking on the rifle length gas system in their 18" barrels.
Looks like someone opened the gas port to .101 from .077 and had no further problems.
This reminds me of an issue I had with a Faxon 7.5" barrel in 300BO short stroking subsonic rounds. Faxon opened up the gas port for me to .101 and it worked flawlessly.

Has anyone else here had problems with PSA 18" uppers in 6.5G?

My 12" PSA works just fine.

Don't want to pull it apart if PSA is going to fix it anyway. But it would make since that 18" with rifle length gas system would need a bigger port size.

Any thoughts?

I've been diagnosing the PSA Gen 2 .308ARs for years, and they always size the gas port small. Seems to be a pattern there. 18" midlength in .308 coming from them with a small 0.070" port diameter, and it should be 0.081" minimum. I sized one up to 0.085" to get it to run on any ammo, garbage, whatever.

That's a PSA thing, and they do NOT get the port diameters right. They're undersized, and that comes from their weak recoil system compromises that they make.

I can go for hours on that, and PSA.

[sharpshooter33]

My 18" RLGS Brux barrel has a 0.094" port and runs great.

is that a rifle length gas system?

I've had the small gas port problem with Faxon on a 7.5" 300Blackout barrel. They fixed it no problem. It was too small to cycle subsonics.

interesting observation about PSA 98Z

from the amount of reviews of the 18" I would say that's probably the problem with them. Lots of barrel makers will just pop the .075 hole on anything without really testing it thru. At least that's been my experience.

I would think if your going to add adjustable gas blocks you would tend to oversize it a little.
with and adjustable gas block you can always dial down. With an undersize hole you can't dial it up lol. Without work.

It will be interesting to see what PSA does. I would say with the amount of reviews of short stroking they should be stopping sales of the 18" and making sure the port problem is fixed. I wonder if they don't realize it is an issue?

Granted I may get it to cycle by lubing up the buffer, but that would mean I'm adding a band-aid to a problem.
My buddy has one also, but he has an A2 buffer system on his. I will be interested in seeing how it does. He hasn't shot it yet.

it would be nice if PSA was more responsive. You can't call, because there sales is separate from the production. They have no "tech's" you can talk to.

I'm gonna mess with it again on my days off, but ultimately I'm probably gonna send it back and ask them to open the port up to .101

Was wondering what size the Monster 18" gas ports are? Also I noticed Faxon uses a intermediate or midlength gas system on theirs.
I'm interested in seeing what size the other rifle length 18" barrel makers are running on their port sizes.

[Bronsonburner]

The one I bought in December ran fine with the gas block closed a bit back from wide open. Brass landed in a neat little pile six feet away at my four o' clock. Too bad I never could get the accuracy I wanted out of it. Last night I pulled the barrel and replaced it with a Criterion Hybrid. Here's to hoping it does better.

[Jakegsxr11]

is that a rifle length gas system?

Yes, rifle length has system (RLGS). I am also running an adjustable gas block slightly closed but I don't run low power (wolf) ammo.

[VASCAR2]

What buffer tube, spring and buffer are you using with your 18” RLGS Sharpshooter33?

[sharpshooter33]

standard CAR buffer and spring. No H2 or H3 or HP spring.

Tried it again today. Temp was around 40 degrees. Fired 3 shots from 3 different magazines and it ejected, but failed to lock back on any. Ejected rounds dropped pretty much around 3 O'clock and about 3 feet away.(roughly)
Wolf ammo. Didn't want to use the Hornady Black since it's expensive and produced the same results at the range the other day.

The response from PSA was: the front screw is the gas adjustment.

Hmmm okay.

Anybody else have experience with the PSA AGB? I thought the front screw would be the locking screw and the side screw which is bigger would be the adjustment screw?
Would have been nice if someone did a manual or youtube on the adjustment. Can't find info on it anywhere. They look like other AGB's, but I've never played with one before this.

[Wanderson]

[montana]

For what ever reason, some barrels are under gassed. Combinations of gas block seal or lack of, bolt carrier leakage," around the firing pin or key", small gas port, worn gas tube, etc will cause short stroking. As a last resort, I have opened up the gas ports on two 5.56 barrels. One was a 20" Faxon pencil barrel and a 16" Bushmaster. Get an accurate measuring gauge and verify your drill bit index. Size no more than .002 at a time. I tape my drill bit for the correct length and insert a cleaning rod so I don't damage the bore. Very easy to do if done correctly. If the gas port is over drilled it is an easy fix with an adjustable gas block. My favorite is the SLR Sentry 7 titanium clamp on adjustable gas block. https://slrrifleworks.com/index.php?...product_id=582 It uses no lock screw and is easy to adjust with 15 settings. Super light and has a bullet proof seal compared to others I have tried.

[sharpshooter33]

Gas blocks come both ways but my PSA 12” has the big adjustment screw up front parallel to the barrel and the small lock screw is on the side perpendicular to the barrel.

I agree though, I had to do some research to figure that out, and PSA has used the other type of gas blocks on other builds, but all the 6.5s PSA make seem to have the same block.

Has it been adjusted? It should have come fully opened. But worth checking. I cut back on the gas quite a bit on my 12” from fully open.

I have a 12" PSA 65 also works fine. I tried to loosen up the lock screw on the side of the gas block today and stripped out 2 allen heads and started to strip the screw. I sent an email to PSA hoping they will fix the problem. I really don'[t wanna tear it apart and check the gas port diameter, but after reading the reviews on the 18"65s on PSA website I believe they are cutting the gas port too small for anyone north of South Carolina shooting an 18" with RLGS and standard power ammo.
I think the bad reviews probably are Northerners. The gas system is just not quite strong enough to cycle wolf steel case or hornady black in 35-40 degree weather. They are located in South Carolina when they test fire these it's probably around 60-70 degrees in the shade. lol

Just my $.02 little salty... it's been a long day and I know it's gonna take awhile for PSA to respond to my email.

Montana thanks for the description on how you open the port up without damaging the barrel. I'm gonna save that in case I have to do one in the future.

[Bronsonburner]

My gas block has the adjustment screw on the side.

[sharpshooter33]

My gas block has the adjustment screw on the side.

I'm going to end up taking some pics of mine. the large silver screw is on the side and the small dark screw is on the front of the gas block. They told me it was the front screw that adjust the gas pressure and the side is the locking screw. Seemed backward to me. Waiting on PSA to email me back about the return for repair.