AR-10 6.5 CM FTEs (Failures to EJECT) Help!

Hellgate

Hellgate

Member
I'm working up a deer load for my brother's PSA AR-10 in 6.5 CM. It has an adjustable gas block. It seems to be inconsistent because we have gotten failures to extract the empty case with both light and heavy loads. The rifle throws the brass out at about 4:30 o'clock. I have what I think is the gas block adjustment screw turned almost all the way out (letting more gas go out the gas port). This is the screw on the right side of the gas block from the shooter's view. The screw in the front of the gas block will not turn. I remember "tuning" the gas block to throw the brass from 2 o'clock (screw all the way in) to 4-5 o'clock and assuming we had enough gas to run the gun. The load we are working at is 40grs W760 under a 129gr Hornady Interbond bullet. The jams result in a case sitting in the ejection port atop the next round that is partially chambered. This is not gonna work for deer season. So, is this an ejector problem or a gas problem. A review of ejection angles would be appreciated. I assume if the gun is throwing brass forward at 2 o'clock it need more gas. When we do not get a jam the bolt locks back just fine. We are running low on bullets so I'd like to get this resolved.
 
Don’t know if it is the same as what I had, but sounds really similar. My build was jamming in about the same kind of way, it ended up being the ejector. Took it to a guy that was an AR armorer, he said it was probably over gassed and causing the ejector to fail somehow. For a cheap few dollar fix we stuck in a new stiffer ejector spring and rubber bumper and been fine ever since. Not sure if its your problem, but with an adjustable gas block I’d try turning it way down and see if that fixes it. I’d disregard ejecting pattern for now, just my opinion.
 
Had the same jamming issue with my bca 243. It would work with a different BCG and a new extractor made it better for a while. I also switched ejectors but none of it made much sense. I finally put a heavy carbine buffer in to slow the BCG down and that seems to have fixed it. It still doesn't sling the spent brass like my ar 15s but it does function.
 
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At the next range session we will choke it down til it fails to lock back then open it up a bit. Thanks for sharing your ideas. This helps.
 
Yeah sounds like extractor spring. Using finger pressure, the extractor should be fairly tough to pivot out from the bolt.
 
Just to clarify what I'm up against:
Which screw is the lock screw and which screw is the regulator screw? The screw in the front of the gas block in line with the barrel seems to do nothing. I was unable to unscrew it until today (at home). The screw on the side of the block seemed to have control over gas flow. Is this correct? It is a Palmetto State Armory adjustable gas block
 
PSA makes good stuff until you get to their AR10 line IMO, they are perhaps the cheapest large frame option and their AR10's are ripe with issues... seen several PSA AR10's jam in the same fashion as well as popping primers, all were .308's though.

Will it at least lock back on a single fired round? Forward ejecting is evidence of too much gas whereas minimal gas, and other issues, is characterized by more rearward ejection.

If it fires a single round and locks the bolt back, then the next step is to narrow down why the spent case is coming off the extractor which is causing the ejector not to do it's job.

I'd also check to make sure the ejector is moving freely in and out and has good spring tension, do this but placing a fired case into the bolt face and rock it into position as if chambered and see if you have strong ejector tension pushing on the case.

If the BCG is actually coming back and picking up a round, and ejection is 3:00 or so, then you could just have a crap extractor and the fired case simply isn't staying captured long enough during the extraction/ejection cycle.

Perhaps try an extractor.

Otherwise, send that upper back to PSA and get a replacement. Their turn around time is generally not bad.
 
PSA sells crap and their customer service sucks. That being said, I have several of their guns. Most needing twiked or parts replaced. What gen is his gun? The gen 3 in 6.5 has duel ejectors as I recall. PSA couldn't get the timing right so they tried forcing the case out quicker. See if his is a single or duel ejector. If single, that may be some of the problem. Now you'll be playing with buffer weight and recoil spring to time it.
 
It is a dual ejector. I toggled in a sized case into the bolt and there seems to be plenty of tension from the ejector springs. Tomorrow I plan on choking down the gas block and opening up the screws til I get 3-4 o'clock ejection with lockback. I"m still unsure of the exact function of the two gas block screws. I finally got the front one unstuck (it won't go in any farther) so I doubt it is functional since it has no effect on the screw on the right side of the gas block. When we turned the side screw all the way in we did not get the BCG to lock back til we unscrewed it about 1/2-3/4 the way out. It has a range of 8 1/2 turns before it comes out. I'm gonna turn it all the way in, shoot one round (expecting no lock back) and then un screw it about 3 turns then another 2-3 turns til I get lock back. It is gonna be 90 degrees here tomorrow so I want positive function for when it is 40 degrees during deer season. A big looming problem is a shortage of bullets (Hornady 129gr Interlocks) to get the job done. I've only got about 20 left (plenty of powder, primers, & cases).
 
I got 2 of the 308s from them for the rrciever sets. My 308 would actually flip the brass 180 in the ejection port. I ended up buying a new bolt and it fixed the issue. A buddy got the 20" rifle and it shot and cycled amazing out of the box. I'd suggest buying a new bolt, the dual ejector was my problem. Granted I didn't mess with it to try and fix, I just replaced it
 
Just swap it. People will say headspace. But in probably 200 ars built, I've never headspace one or had any issues. I bought a Wilson combat bolt for mine. The other is aero
 
It's a Wilson combat match barrel we put into the PSA upper. We could not get decent grouping with the PSA barrel.

We took it to the range this AM and choked the gas block all the way down. No extraction or bolt movement there . We loosened the adjusting screw two full turns (8 1/2 turns will remove it). The gun now fires, ejects, & reloads another round from a full mag (5 rounds). We had no jams. We have it sighted in for 200 yds. It's shooting just a little over 1 MOA.
 
HG

What type of buffer spring/lower receiver set up are you running?

My 308 started out as a carbine lower with problems, then evolved into a rifle lower with a rifle buffer and Tub spring.

No adjustable gas bloc and it runs perfect.
 
The rifle started out as a Palmetto State Armory package (both upper & lower). The groups we were getting were 1.5-2" with handloads so we bought Wilson Combat 18" (only one available) SS match barrel and now are getting 1-1.25" groups. The last 15 rounds functioned fine.
 
The gun now ejects a 4 o'clock and no jams in 15 rounds. If we have a problem I will back out the gas block adjustment screw another turn. It is backed out two full turns now from fully choked down.
 


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