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Help. AR ejection issue.

13 points · submitted Mar 2026 by u/MapDiscombobulated40

Recently bought this PWS second hand. First owner claimed he only shot around 200 rounds an it appears that way.

Right before he sold it to me he swapped back in the stock trigger. Previously had a Geissele trigger.

PWS MKIII Mod-2

I’ve taken it twice to the range and shot it suppressed and unsuppressed. Both times I’ve run into the same issue and trying to figure out what the hell is happening.

Rifle shoots perfectly fine both suppressed and unsuppresed. However. Let’s say in middle of shooting you want to stop & unload it. When I remove the mag and go to eject the live round via charging handle. The charging handle is frozen. Will not budge. Mortaring didn’t work. Didn’t try a mallet or anything. This has happened on both range trips. Only way to remove round is shoot it and it ejects normally.

What could the cause be? I just got home from the range and wanted to confirm it would do it again and it sure did. Going to try to inspect everything but would be helpful if anyone had similar issues or point out something I should look for.

Help. AR ejection issue.

15 comments · 90% upvoted · source · other discussions

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Emotional_Town_1500 11 points · Mar 2026

It might be a headspace issue, to be specific, too tight of a headspace

MapDiscombobulated40 [OP] 4 points · Mar 2026

https://preview.redd.it/86h93sqwp3sg1.jpeg?width=3141&format=pjpg&auto=webp&s=d7c84f40bfd3f7d0147fe00ba2fb3a501c9696b1

Metal shavings on bolt and the cam pin has a lot of wear marks on 2 sides. Completely removed coating.

Frequent-Compote-908 3 points · Mar 2026

Feed it a dummy then take the upper off the lower with the dummy round in it. Go from there: snap cap or your preferred training dummy 🤘

MapDiscombobulated40 [OP] 3 points · Mar 2026

I’ll do that. I fed a mag of snap caps and every one of them ejected without issue. Not sure if it’s when it gets hot or what.

Apprehensive_Box2087 3 points · Mar 2026

The piston is dirty, needs to be cleaned and oiled really well. It happens to my pws at the end of hunting season.

MapDiscombobulated40 [OP] 1 points · Mar 2026

Are you saying the section circles needs cleaned and is the reason my charging handle is getting stuck ?

https://preview.redd.it/3iss60eu68sg1.png?width=1418&format=png&auto=webp&s=b313d263c084ab1b0b0b104746841c2319a7a022

Doesn’t explain the shavings of metal in my BCG. I’m guessing something is out of tolerance

Apprehensive_Box2087 1 points · Mar 2026

We might have a different issue. But when my bolt is getting super stuck, it’s cause that piston head is super gunked up.

McClutchin_02 3 points · Mar 2026

Maybe the barrel ramp is out of spec ? Causing the shell casing to shave off.

Frequent-Compote-908 2 points · Mar 2026

Ya that’s weird

MapDiscombobulated40 [OP] 2 points · Mar 2026

Just took it apart. We have metal shavings from? It looks like the pin to the bolt. My first long stroke piston rifle so a few alien things to me.

https://preview.redd.it/o6yfvozop3sg1.jpeg?width=3024&format=pjpg&auto=webp&s=e1d5ac8141224fc2af6cca3d4dc0565deb30a4a7

MapDiscombobulated40 [OP] 2 points · Mar 2026

https://preview.redd.it/wnv622heq3sg1.jpeg?width=1688&format=pjpg&auto=webp&s=4885ac8871fd759c0d6c553db35523259eb111b7

anonymity76 1 points · Mar 2026

Not sure if this is your first AR, but the general rule is: run them wet. They LOVE lube more than your girl does.

Especially if you're getting metal shavings, this thing needs some lube love and of course, start checking clearances

Buy a go and no-go gauge set. Although it's ALMOST unlikely that you have compromised head space, it's not impossible. And if you do, you can swap in a different BCG and measure it. If it is still out of spec, then you are left with barrel replacement or a bad upper receiver.

With AR's, the upper receiver and barrel are built so that you don't need to measure bolt gap as it's really not something you can fix unless you somehow can add or subtract material on the lip of the barrel that seats against the receiver when you install it.

Metal shavings are possible from lack of lube and grinding on the bcg-receiver contact points, the bcg ramp-trigger contact points, the charging handle to gas key contact points, or even the buffer to buffer tube contact points.

MapDiscombobulated40 [OP] 2 points · Mar 2026

I own many AR15s however, this is my first long stroke piston AR15. She was WET, soul glo wet in all the right places. Something has to be out of spec & wonky, I suspect something with the BCG.

The wear on the cam pin for such low rounds is what is sticking out to me. I emailed the company pictures, waiting to see what they say. I'm guessing they will request for me to send in (hopefully) just the upper for warranty.

anonymity76 2 points · Mar 2026

Ahhh... Now it makes sense.

I didn't realize it was a piston build

1) i assume that the bolt has had the gas rings removed? If yes...

2) is there a spring on the tail of the bolt when it's inside the bolt carrier?

When i did my first "from scratch" piston build, I did a LOT of reading.

There are two things that happen a LOT in piston builds, both avoidable

1) the cam pins can move more because there's no tension from the gas rings holding tension on the bolt inside the carrier. This can cause wear on both the cam pin and your receiver. They actually MAKE a rounded top cam pin exactly because of this. Buy it

2) when the gas rings are removed, the bolt can get "sloppy" in the carrier. Often it can and will not seat as cleanly when going into battery. There is also a spring kit that someone makes that has the exact correct size to slide over the tail of the bolt and fit nicely in the carrier. Generally this spring never wears out and it keeps pressure on the bolt to keep it from bouncing around during cycling.

I see the spring in your pics. But still... read up on the cam pin with a rounded top specifically in piston builds

Check your receiver where the cam pin rides. See if it's shaving the receiver down (as it's steel snd and your receiver is aluminum, you'll see the scape marks on the receiver if they are there

The Spring: https://adamsarms.net/product/bolt-spring/

The cam pin:

https://www.lantac-usa.com/product-page/cp-r360-cam-pin

MapDiscombobulated40 [OP] 1 points · Mar 2026

I appreciate the info, never heard about the rounded cam pins. Going to do a bit of reading on that one. I'm almost 90% there is 0 wear/scraping on the receiver but I need to clean it completely to be sure of that. It would make sense though because I'm unsure where those metal shavings came from, I guess I could use a magnet to see if the metal flakes are ferrous or not. Did not hear back from PWS today after pictures were sent to the rep that contact me. Hopefully tomorrow.

Thanks for the info, I will update this thread once it's all figured out.