The bolt on my Palmetto Glock-magazine, billet lower, AR-9 was hitting the ejector as the bolt traveled forward. The ejector was scored on the right side, and dented on the back where the bolt was first making contact. The lower, which I bought complete from PSA, is mated to a complete PSA upper with a 7.5" barrel.



Regardless of hitting the ejector, my AR-9 would operate flawlessly. I was more concerned about long term wear, and wanted the bolt to travel more smoothly.

Palmetto will fix this for their customers, but my lower is a registered SBR and I am LOATHE to ship it anywhere. As a proud alumnus of the Wile E. Coyote School of Gunsmithing (WECSOG) I decided to shim the ejector myself.

I first loosened the two Allen-head screws on the left side of the AR9 with an 1/8" Allen wrench. The screws hold the ejector in place with just pressure, screws were not Loctited. Loosen the screws and the ejector lifts out of it's recess in the lower.  



To make the shim I used a of sheet of brass that mikes out at .01" thick. I traced the outline of the bottom half of the ejector onto the sheet brass and cut it out with a titanium bladed scissors. I didn't want any of the shim to be exposed outside the ejector recess, so I inserted the ejector and shim back into the recess in the lower, and used a pencil to mark where the shim needed to be trimmed.  Snip, snip, perfect fit. Put the shim on the right side of the ejector, dropped them into their recess in the lower, and tightened down the Allen-head screws. Reassembled the rifle, the bolt now moves in it's channel much more smoothly. Off to the range to test.

Fired a few rounds without problem, and then opened up the gun to make certain the ejector had not shifted. It had not moved, it was rock solid. Inserted a fully loaded 33-round Glock mag and let 'er rip. All empties ejected cleanly. Inspected ejector, and again it had not moved. Inserted a second 33-round Glock mag and emptied that without incident.

Ejector passed the final inspection. Degreased the Allen head screws and screw holes, added Loctite and reinstalled. I'm declaring victory.

OP...thank you for posting this fix for those with PSA lower ejector issues.

I would ask that you try and post some pics for those less mechanically inclined.

Other than that...nice job.




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Is your lower a billet or classic?

Billet. Will add to original post.

NOW with pictures! In the image with the ejector you can just make out the top edge of the brass shim.

Thanks, I have the same lower, same wear. I'll try the mod

How about a beer can?

Oh, and to the OP, thanks for posting.

I like this idea...i got tons of those!

I first thought of cutting a section out of a beverage can. But when I measured the thickness of the aluminum it came in at .002", and I looking to make a shim of about .01" or 5 times the thickness of the aluminum from the can.

Aluminum deforms.  The feeler gauge suggestion above is a great idea.

The feeler gauge idea IS a great idea. Thanks Mad-Machinist. Gotta remember that one.

What's the best way to bend the gauge to get a clean break?

And then how would you do any post-break shaping? Sand it, or could you use a file?

Good stuff here for me to remember when I get that far. I am building a palmetto ar-9 9mm so I better keep a eye on this.

THANK YOU!   I got the impression when I contacted them that they thought that there is no such issue.

I'm in the exact same position (same reluctance to ship, same reasons, same issue). You mention that they will now fix this issue for customers... what is their fix?  A factory application of your DIY solution? New (different/modified/etc) parts?

If this fix works fine, I am open to giving it a try. If PSA's solution is is replacement with parts that aren't defective or poorly mated out of the box, I would rather have that solution, provided I don't have to send them the firearm.

It's not just yours, they all do that.  If you're using a PSA billet lower with a PSA bolt anyway.

Easiest fix is to dump the PSA bolt.  Switched mine out with a QC10 and the QC10 bolt doesn't touch the ejector at all.

Hmmm, new $200+ bolt or a piece of scrap metal?

Well the PSA bolt isn't compatible with LAW folders either, so I killed 2 birds with 1 stone.

Sad that PSA still hasn't figured out how to make a bolt that doesn't bang into the ejector on every pass.  Several of us let them know about the issue when they first released their 9mm lowers and uppers, and they said nothing to worry about it's just cosmetic.  Internal parts colliding and removing metal from each other seems like more than just cosmetic to me, but whatever.

I agree. Retracting the bolt was much harder without the shim, definitely lots of friction between the two assemblies. My understanding is that if you send PSA your lower the fix they will apply is also a shim.

Used my PA-X9 in last week's USPSA match. Ran flawlessly.