PSA 18" upper short stroking. Anyone else?

[Gusmeister]

When I got my 20" Odin works barrel 18 months ago (built the rifle) I had all sorts of feeding/ejection problems. The chamber was a bit rough and that delays extraction. They fixed that. Plus all the other problems went away with keeping the BCG wet and shooting it. If you end up sending it back you might want to have them look at the chamber. Other than that I suggest you go back and review everything from the gas block back and make sure the only possible problem is with the barrel itself. Opening up the gas port may truly be the problem but if it isn't you'll be over gassed. Try a carbine buffer and make sure your buffer spring is not over powered. Have fun. You'll be smarter when this is over.

[Bronsonburner]

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.

Sounds like the same one I have. The silver screw on the side is the adjustment. It may be they use whatever style is closer to the assembler that day.

[sharpshooter33]

Sounds like the same one I have. The silver screw on the side is the adjustment. It may be they use whatever style is closer to the assembler that day.

so have you adjusted yours? if so did you loosen the front screw 1st? That would explain why I was stripping my allen wrench on the side screw.

[mikeO38]

I had the same issue with my 18" rifle length gas PSA uppper. Had it on a rifle with stock carbine buffer spring and standard buffer. Gas adjustment was open all the way and it would not lock back the bolt on Federal Fusion. It sometimes wouldn't even pick up the next round with Hornady SST, which was running almost 100fps slower than the fusion.

I ended up drilling out the gas port, cant remember what I took it to but if I remember right I think it was .98, this solved that problem. This ended up being the least of my problems with the upper. Had poor accuracy and point of impact shifts. To make a long story short I pulled the barrel, trued up receiver face, threw away the POS aluminum barrel nut PSA used and replaced it with a Midwest Industries steel barrel nut. Got group sizes down around 1.5 MOA but never solved the POI shifts I was getting. I am now building another upper to replace this one and scavenged the bolt and charging handle, the rest is sitting in a scrap box.

[mikeO38]

Typing error on that gas port size .098, sorry

[sharpshooter33]

yup. Checked the Monster 18 barrels here are .098. I'm betting PSA is poppin them around .077 or so.
Mike038 do you live in the Northern states by chance? I'm thinking their complaints are coming from colder areas also. The lack of gas would show more with colder temps.

Anyway here is some pics I took today. Thanks Bronsonburner for correcting the info I got from PSA. I tried the front screw 1st and it unlocked both. I screwed the gas port screw all the way out. then put it back in enough to get a good seal. pics below. Still would not cycle. Everything looks aligned, gas rings are fine. Upper and BCG don't look like they are getting much gas. Not much to clean off back there.
I'm pretty sure this is a gas port diameter problem. They probably were in a hurry to jump in the market and didn't really catch the need for a bigger gas port and being in North Caroline they may have been able to get them to cycle when they tested them originally.
I'm just stabbing at it here since I'm not an engineer and just a gun nut.
My barrel has been grouping well when cycled like a bolt action lol. I don't hold it against PSA. At least they were planning the 18" to shoot suppressed and used the RLGS. Faxon is using a midlength which if your using a suppressor your probably gonna want a AGB.

I'm glad the Monster group buy used the RLGS in it's 18" and he put a .098 gas port in it. I may squirrel one of those away from a future build.
I got bit by the Grendel bug pretty hard this year and so did my wallet.

thanks guys for the input and here's some pics for those that have the PSA AGB
silver screw on the side is the gas adjustment. Black screw on the front of the GB is the set screw you loosen before making adjustments with the silver one. HTH anyone else.
IMG_20190215_163608341_zpsin3a0eby.jpg
IMG_20190215_163551972_zpsaykschau.jpg
IMG_20190215_163626300_zpsdg60npyr.jpg

[mikeO38]

Sharpshooter 33 , I'm from Missouri. When I was shooting the PSA upper it was probably in the low to mid 30's. After I drilled it out and tried it again with I believe .098, it was still in the 30's if I remember right and cycled fine with gas port all the way open. Threw the brass in a nice pile at about the 4 to 4:30 position.

[Bronsonburner]

so have you adjusted yours? if so did you loosen the front screw 1st? That would explain why I was stripping my allen wrench on the side screw.

Yes. I damn near stripped it out too lol.

[98Z]

For an adjustable gas block on a new build, start with it wide open. Full gas. After you function check the rifle, then start dialing it down.

For comparison on gas port diameter, my Ballistic Advantage 6.5 Grendel Mk 12 SPR profile, heavy stainless, rifle gas, 0.750" gas block diameter, measured out a 0.100" gas port diameter.

My Faxon Firearms 6.5 Grendel gas port info: Match Series- 18" Gunner, 6.5 Grendel, Midlength Gas System, 0.750" gas block diameter, 416-R, 5R, Nitride, Nickel Teflon Extension - Gas Port diameter = 0.077".

Seems PSA is having issues with port diameter on the .308s and the Grendels. Looks like a midlength-sized port in that rifle gas barrel from them. Instead of sending it back, and getting it returned from them, with them stating its fine, I'd save the time, headaches and shipping money to them - and drill it up myself. Stick a .250" diameter wooden dowel down your barrel, to protect the other side of the barrel, use a good bit, and drill slow with light pressure.

[sharpshooter33]

For an adjustable gas block on a new build, start with it wide open. Full gas. After you function check the rifle, then start dialing it down.

For comparison on gas port diameter, my Ballistic Advantage 6.5 Grendel Mk 12 SPR profile, heavy stainless, rifle gas, 0.750" gas block diameter, measured out a 0.100" gas port diameter.

My Faxon Firearms 6.5 Grendel gas port info: Match Series- 18" Gunner, 6.5 Grendel, Midlength Gas System, 0.750" gas block diameter, 416-R, 5R, Nitride, Nickel Teflon Extension - Gas Port diameter = 0.077".

Seems PSA is having issues with port diameter on the .308s and the Grendels. Looks like a midlength-sized port in that rifle gas barrel from them. Instead of sending it back, and getting it returned from them, with them stating its fine, I'd save the time, headaches and shipping money to them - and drill it up myself. Stick a .250" diameter wooden dowel down your barrel, to protect the other side of the barrel, use a good bit, and drill slow with light pressure.

That's what a suspect is the issue without taking it down and after checking all the other possible gas leaks without taking it apart. I've been in contact with one of their peeps on AR15.com
I believe they didn't know about the gas port diameter that should have been cut. I think they were in a hurry to pump the barrels out so they could hit the market. Or when they tested they did in hot weather with a full length buffer system.
I could tear it down and do the work myself, but why mess with it if they have a life time guarantee. If I mess it up it's on me then.
I'm not the most mechanically inclined. I could probably get it done, but just not worth it to me when I can still shoot my 65G bolt gun or 12" until it gets fixed.
They said they would pay for shipping both ways so no out of pocket.
Anyway 98Z glad you gave me the measurements. I had the almost exact issue with a 7.5" 300blackout build. Had a Faxon barrel that had undersized port. It was opened up to .098-.101 and they he took subs like a champ. Faxon also took it back and fixed it.
Both companies have been very customer friendly.
Also thanks to the guys here for offering advise.

[98Z]

I believe they didn't know about the gas port diameter that should have been cut.

I've been dealing with their .308s for a few years now, first through the original (Gen 1) and then the Gen 2. The Gen 2 fixed most of the hardware issues that they had, but had functional problems. Most people think that their .308s are "over-gassed" and the common recommendation from all over the 'net is "Add adjustable gas block!" Theey're not over gassed, they are under-recoiled, with a bad recoil system design (spring dimensions, buffer weight and receiver extension internal depth). That adjustable gas block is only a bandaid to try to cure another problem. Put a proper recoil system in one of them, and the gas port is too small... So, in a round about way, the adjustable gas block dialed-down, cured a gas block that was too small... I had one of their carbine receiver extensions in my hands that was 8.000" internal depth... ridiculous.

For run-of-the-mill entry level guns, you'd have to treat it like a tuned JP Rifles competition gun. All it took to fix one of the 18" MLGS .308 guns was an Armalite AR-10 carbine recoil system replacement, and taking the gas port from the low 0.070"s to 0.086". It digested everything, after that.

I had that rifle shipped from TX to AZ, and fixed it myself, just so I could see what they were doing on that platform, just to get the knowledge on it. The owner never sent it back in to them, with so many other reports of people sending it on to them, and the return report of "Nothing noted, rifle functions as designed." In the .308 world, their guns have been pretty frustrating, in this internet world. Everybody that has a problem searches it online, joins a place, and starts complaining. On the other side of that, you get tired of diagnosing it, time after time. I have a large series of frustrating "solutions" to the .308 stuff I've seen from them.

If you get the rifle back from them, and you get the report that it's just fine - punch the gas port to something close to 0.100" and run it. It'll work. Start low, and work up. You can't make the port smaller after you drill it, unless you run adjustable gas.
"

[sharpshooter33]

yup. if they send it back and it still has problems, I'll be doing my 1st gas port enlargement.

[98Z]

yup. if they send it back and it still has problems, I'll be doing my 1st gas port enlargement.

It's really a very easy thing to do, man- don't sweat it if it comes to that. If you start thinking about the time involved in sending, receiving, and all that - and the potential that they think it's "quite alright," and give you a nothing-report on it... - I'd just save the headaches and punch it myself.

They still haven't figured out the .308 gas port diameters yet, after a few years now (what they really haven't figured out is the recoil system, and the corresponding gas port diameters). There's no way they have the Grendel stuff solved...

Don't send it -drill it, and get on with life.

[98Z]

Or send it to me - I'll do the work, and get it right back to you. I solved it for a .308 guy and got it right back to him the next week. What that gives me is the information on what they're doing, and how far off it is. You get a functional rifle - I gain the information of what they're doing wrong, and I provide results in the future, until they decide to change what they're doing to the "average customer."

Here's the drama I went through with the .308 upper I had in-hand, and fixed. The "drama" mainly came from the company fan-boi that wanted to keep it up. I fixed their gun, that's the bottom line, and they sent it out to the owner that way. Lifetime guarantee on it or not, it left the factory non-functional.

https://forum.308ar.com/topic/16527-continuation-of-gophers-issues/

They certainly do not have Grendel figured out yet. They don't have .308 Win figured out yet, either. How many years at that one, now?... They crush the 5.56 guns, though. More power to them on that one.

[sharpshooter33]

Got mine back within a week! I sent it out expecting to not hear anything for awhile, but the next week it arrived via UPS.
Put it together and it cycles fine with everything I feed it. Talked to Josiah via AR15.com and he said they were aware that some had made it out without the correct port size. They fixed it up and I'm back to running it.
Now if I can get my eye sight working with my old eyes maybe I can get some good groups. Only ran about 20 rounds thru it so far. Sighted in and ready to see if I can come up with a magic formula for some 123gr bullets.