PSA AR9 not cycling 147gr

[Armymutt]

I have a PSA AR9 SBR that cycles 115gr rounds just fine, but doesn't work with 147s. The case usually gets extracted, but not ejected. Sometimes the next round in the mag gets stripped, but the fired case gets trapped in the works. I have yet to get an undamaged case out of the rifle after firing a 147. Buffer issue? Bolt issue?

 

[farmerboy78]

I could be wrong, but it sounds like the heavier load isn't producing enough pressure to correctly operate the action. May try a little lighter buffer/ spring combo.

 

[Wreck-n-Crew]

I could be wrong, but it sounds like the heavier load isn't producing enough pressure to correctly operate the action. May try a little lighter buffer/ spring combo.

^^^ that or if you can bump that load up without going over before going with a lighter buffer/spring it might get you there.

What's your powder and charge?

Edit: Sorry thought I was in the reloading section and those were handloads.......lighter buffer and spring.

 

[Walkalong]

I agree, it sounds like it simply isn't stout enough to cycle the weapon.

 

[carbine85]

My AR9 doesn't cycle 147 gr rounds reliably. I normally get a FTF.
It's 100% reliable with the lighter bullets.
I wouldn't change out the buffer for the heavier rounds. I would just stick with the lighter ammo.
With that said I tend to agree with the lighter buffer or spring.

 

[bfoosh006]

Armymutt..

Could we get more specific details about the SBR... barrel length, suppressed, buffer weight and specific spring, trigger, Colt pattern, Glock, what mag block ....

And believe it or not.... are you using a brass catcher ?

My 16" PSA Colt Pattern runs flawlessly with all weight ammo I have tried..... and that is with a .308 Tubbs Flatwire and a 8.5oz solid buffer.

 

[jmorris]

Who's ammunition? I run 147's almost exclusively in mine and not even stout loads rather subsonic "minor" loads.

 

[bfoosh006]

My AR9 doesn't cycle 147 gr rounds reliably. I normally get a FTF.
It's 100% reliable with the lighter bullets.
I wouldn't change out the buffer for the heavier rounds. I would just stick with the lighter ammo.
With that said I tend to agree with the lighter buffer or spring.

Have you tried polishing the feed ramps ? I did polished mine for HST ammo.... huge improvement.

 

[Armymutt]

It's a 7.5" barrel. Colt pattern lower, PSA mags. Had a SilencerCo Hybrid on it. Don't have the specs on the lower - it's a standard PSA 9mm lower. I tried it with and without the brass catcher - no difference.
The ammo is a 147gr Xtreme bullets over 4.3gr of Winchester WSF. Worked well in a Glock 19 and Sig 226 with the same can, with piston of course.
I haven't polished the feed ramps. The rifle has maybe 20 rounds through it so far. It's eventual purpose will be suppressed home defense.

 

[rbernie]

The 9x19 AR-15 upper is a simple blowback action. If you have an issue with a load going BANG! but not completing the extract/eject/feed cycle, the implication is that the load isn't hot enough to cycle the gun in its current configuration.

If you're running a H3 or '9mm' buffer, try switching to an H2 or standard carbine buffer. The reciprocating mass of the AR is likely to be greater than the reciprocating mass of, say, the G19.

 

[Armymutt]

I just ran about 5 rounds of 115gr Winchester white box through it, no can, different mag. Same issue. The first round failed to eject, but the bolt came back far enough to strip another round from the mag. The rest ran just fine. I'll try swapping in a carbine buffer.

 

[rbernie]

While you're at it - check to make sure that the pinned ejector is intact.

 

[jmorris]

I just ran about 5 rounds of 115gr Winchester white box through it, no can, different mag. Same issue.

You might be able to narrow down the problem then. What did you change other than the mag to go from it running "just fine" in the OP to it not running today?

 

[wally]

While you're at it - check to make sure that the pinned ejector is intact.

And the extractor. If its picking up the next round the buffer and spring is not the issue.

I shoot lots of plated 147gr loaded with 4.1gr Unique suppressed and un-suppressed in our three 9mm AR SBRs. Actually 3.9gr was fine in the AR and everything but my Glocks so I had to bump it to 4.1gr as I won't do different loads for different guns.

I first started with a ProMag block while waiting for my back-ordered Hahn block, it worked for a while then started having ejection failures. The ejector worked loose. I wedged it tight again with epoxy putty and got by with it until the Hahn finally arrived.

 

[Elkins45]

My PSA (Glock mags) has the exact opposite problem: I switched tubes and poured a standard rifle buffer full of lead just to keep it from opening prematurely.

 

[Armymutt]

Finally got it sent in to PSA and heard back. They think it's a barrel issue affecting all their 9mm rifles. They were at the coaters last week. Hopefully I'll get an update soon.

 

[wally]

While you're at it - check to make sure that the pinned ejector is intact.

And not loose. I've a 4" 9mm SBR and run the heaviest buffer I could find and its just fine with 147gr ammo. I did have a few outings with stovepipe issues -- turned out the ejector was loose enough that sometimes the empties hit the side instead of the face. I degreased it with brake parts cleaner and then made it stay put with epoxy putty in its slot. Problem solved.