One of the main issues encountered after completing your Polymer 80 build is surrounding your slide.
There are a ton of common, yet easily fixable related to p80 slides including not cycling, not returning to battery, failure to go into battery, slide release problems, and issues with the slide going on/coming off.
The good news is that with some mostly quick fixes the p80 slide issues can be remedied.
We draw from our own experience building Polymer 80s and questions asked around the internet to help you get your 80% build working and slide functioning like butter!
P80 Slide Not Cycling
Owning a fancy DIY-built Glock aka Polymer 80 that won’t cycle will have you feeling like you now have a single-shot musket.
If your p80 slide is not cycling it is often due to the following issues:
Your P80 is Dirty
You need to disassemble your gun and clean the rails, slide, and barrel. You should then apply gun lube to the rails (a small dab will do you) and allow it to run down the slide using gravity.
You can also apply a small dab to the ejector area to keep all the internals functioning smoothly.
Your Channel Liner is Not cleared out Enough
You need to bring the plastic/polymer down so it is flush with the channel in your Polymer 80.
If this is your first build, KEEP SANDING, people often underestimate how far they need to go when it comes to sanding, followed by increasing the grits to get the action area smooth.
A few other things that can help with your slide cycling include upgrading the recoil spring to stainless steel, upgrading to a “no fail” ejector, and using as many Glock OEM parts as possible.
It is easy to assume that this is the issue off the bat but often it is one of the aforementioned issues and related to build finish quality.
P80 Slide Not Returning to Battery
If your P80 slide will not go into or return to battery this can again be related to not removing enough of the channel liners or not sanding your rear tabs completely smooth.
Another often overlooked issue is you are touching the slide release when firing your Polymer 80. This will prevent your gone from going back into batter and will keep the slide locked back.
In order to test if this is what you are doing try the following:
- Insert the magazine into your Polymer 80
- Chamber a single round into the slide
- Remove the magazine from your pistol
- Fire a round
Try all of the following and you should be able to get past any battery issues with your Poly 80 slide.
P80 Slide Release Not Working
If the slide locks back that is due to your finger bumping the slide release or you have installed the slide takedown lever incorrectly on your P80.
You will first install the trigger, locking block, and pin before then installing the slide lock lever to ensure it is pinned down firmly in the correct place.
You can also purchase an OEM or upgraded slide release as a last resort to fix this issue.
You can find a ton of options for Polymer 80 slides as they use the same slide release parts as Glocks.
Polymer 80 Slide Not Locking Back
While not as much of a pain as your slide not going back into battery it is still a pain if your P80 does not lock back after the last round is fired.
This can be related to a few issues:
The magazine may be out of spec or have issues – you can try using OEM Glock magazines to cross this problem off your list.
Channel Liner Issue
The slide recoil spring is rubbing against the channel liner – you can deep dive into this issue by applying a bit of pencil or marker to the bottom of the “U” in your channel liner area.
Rack your P80 slide back and forth and if any of the markings rub off you need to sand even further.
Polymer 80 Slide Won’t Rack
If your Polymer 80 slide won’t rack the issue is likely the same with all of the following models:
- Polymer 80 PF409C G19
- Polymer 80 PF409SC G26
- Polymer 80 PF409v2 G17
Recoil Spring is Getting Stuck
This would be due to the “U” part of the channel liner not being flush enough with the Polymer of the frame.
This will guarantee that your slide will not rack or at least get stuck easily. Never stop sanding!
Lube your P80 Rails!
Like many things in life “grease fixes the sticker wheel” add a little lube to the slide and rails and then rack the Polymer 80 several hundred times (not exaggerating).
This is a brand-new gun, you need to break it in.
Tab Height & Rail Seating
It is easy to have your rails sitting just a bit too high and the slight height inconsistency, while not obvious, will cause your slide to have issues being racked or slid back.
Sand your tabs even further and make sure the rear rails and front locking block are pushed and seated all the way down into the frame.
P80 Slide Installation Issues
Many of the most common issues when building your P80 will be clear right away when you first install your slide or take it off.
Polymer 80 Slide Won’t Come Off
This can happen due to your lower parts kit being installed incorrectly or also due to channel liner clearance issues.
If your slide is stuck on the P80 frame you can always remove the rear rail pin and locking block pins and pop the entire gun out in one move.
It is then suggested you review a few videos related to P80 LPK (lower parts kit) installation and take your time reassembling your gun before trying to install the slide again.
Polymer 80 Slide Won’t Go On
If the P80 slide won’t go on this is 100% a rail installation issue.
The rails are not seated down into the frame all of the way. Tapping them with an armour hammer or giving them a good old push (even bang) can help slide them into place.
This can also be a more permanent issue related to your pin holes. If you drilled the rail/locking block holes incorrectly it could still allow you to complete the Polymer 80 but the rails will be sitting out of alignment.
Are Polymer 80s Reliable
While this article may give you the idea that Polymer 80s are less than reliable, we hope we did not scare you off.
P80s are all about patience, taking your time, and “first time build” quality. When done correctly and taking the proper break-in steps(racking the slide, dry firing your P80, and the suggested 200-round break-in period).
The vast majority of Polymer 80s are just as reliable as OEM Glocks.
The issues arise with the slide due to this part being the final piece of the puzzle.
The installation of the slide will bring any imperfections to light. The good news is if you follow these tips you can narrow down and remedy the issue.
Building a Polymer 80 is a learning experience but if done well can be rewarding and land you with a rock-solid and reliable handgun.