Polymer80 Glock Build Troubleshooting

If you haven’t heard about Polymer80, they make a number of 80% receivers including some remarkable Glock compatible frames. Now they aren’t just a cheap gimmick – I like the grip angle, the texture and the finger relief that all result in a far better feeling pistol than an actual Glock in my opinion. Now there are haters that say these are not Glocks – that’s fine, they aren’t. Then again, it’s not like we all buy ARs only made by Colt or Armalite either in comparison.

So I have been posting about how to do the builds [Click here for a Glock 17 using the PF940V2 frame post and here for one on Glock 19 using the PF940C frame post]. They are very straight forward, fun and can generate a reliable pistol. Like all things, there can be challenges and troubleshooting your build to understand why the slide is binding, the trigger isn’t resetting and so forth are all things that may happen. Luckily, there are also lots of videos and posts for understanding how to solve the challenges.

Be Sure to Read the Instructions First

I do recommend you read the instructions from Polymer80 before you do your build. If you didn’t read them and are now having challenges, I would recommend you go back and read the good instruction file they wrote and watch the video:

Troubleshooting Videos



Also, Pew Pew Tactical did a nice series of posts on building and troubleshooting Polymer80 builds. Click here to open a new tab and go there.

My Take On Common Issues

  • The slide doesn’t go all the way back: Check that the recoil spring is not catching on the channel you needed to mill out. Check that the slide stop spring is sitting flush and not catching on the spring. Sometimes plastic falls into that channel and keeps it from fully seating. (It would be a good idea to blow your frame out with compressed air to get all the loose plastic out). [Note, we have a tool to aid in the sanding of the barrel block area, click here to read about it]
  • Trigger not resetting – this is either an issue with how Polymer80 did some of the Rear Rail Modules (RRMs) or how the frame was drilled causing the RRM to move. If this happens, you will need to file a bit off the right side (when looking down at the receiver) of the RRM so the trigger bar doesn’t hit it. I’d also recommend checking that there aren’t burs/machining imperfections on any of the trigger’s metal parts that might cause binding.
  • Slide not cycling smoothly – The rail modules should be equal height. Again, there may have been an issue with drilling causing an alignment issue. See if you can bend/adjust the rail modules so they line up.
  • Trigger feels gritty – remove the trigger and polish all metal surfaces. Blow out the pistol and trigger areas to ensure there isn’t any plastic debris. Expect it to take a couple hundred rounds to smooth out.
  • Action feels gritty – again, polish everything. I like the small rubberized polishing bits for the Dremel as well as working with sandpaper up to 2000 grit. Always remember that your goal is to smooth and polish, not to remove a ton of material. Another option is to simply let the parts get to know each other and wear in. A ton of grittiness will disappear with use.
  • Slide seems to lock open at times – this is likely due to the recoil spring catching on plastic left in the barrel block area. Click here to read more and to see our tool that can help.
  • The pistol doubles, meaning it fires on the pull of the trigger and the release. This is most likely caused by using an aftermarket connector. If you are not using an OEM Glock connector, try using one and see what happens. I did a post about this if you’d like to read more, click here.

So, I hope this helps you out. Polymer80 Glock frames are well engineered and do work. There may be some issues you need to work through due to how you build the pistol and the parts you use but view overcoming them as part of your journey and don’t give up. The end result is definitely work it.

Polymer80 and Glock Parts Vendors

When you want to customize your Polymer80 or Glock, or you need replacement parts, there are a number of solid vendors you can go to:

Those are all reputable vendors and aren’t going to sell you inferior counterfeit products.


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Please note that any images shown were extracted from the videos and remain the property of their respective owner(s).