Why Is My Polymer80 Slide Randomly Locking Open?

I don’t claim to be a Glock or Polymer80 guru by any means and I just learned a little detail that makes a world of difference. My problem was that with both my PF940v2 based Glock 34-style and PF940CL based Glock 17/19 hybrid, my bolts would lock open once in a while randomly. To be clear, I don’t mean they would stick open at some spot – the slide stop lever was engaging and locking the slides open.

I do have a blog post about what to do if your slide is sticking open / getting caught part way during its operating cycle. Click here for that one.

These random acts were far more frequent in the PF940CL and were driving me nuts. During a careful inspection, I noticed that the slide stop lever of the PF940CL had very, very little spring resistance pushing it down against the frame. More or less, the lever was flopping around!!

The first thing to check was whether I assembled it correctly or not. The spring on the slide stop lever should be under, or captured by, the top locking block pin. If it is not, then there isn’t enough tension to keep the lever down and it could then flop around and lock the slide open. In this case, it was fine.

Not the best angle in the world but see the orange circle in the above photo? It is the end of the slide stop lever’s spring sticking out from under the top locking block pin.

So, it was assembled right but another thing struck me as odd. While it was stamped with the Glock part number for the G34’s lever, the finish had always struck me as off vs. other Glock parts. I bought the lever off eBay and suspect I was the victim of an inferior counterfeit part that had a weak spring.

Notice how the black finish has worn off the Slide Stop Lever. I’ve not used the pistol enough to wear the finish off that fast and was one of my prime reasons for thinking I was sold a counterfeit/inferior slide stop lever.

Enter Vickers Tactical & The VTSS-001

I decided something must be up with the two Glock-34 extended slide lock levers that I bought off eBay – as in maybe they were counterfeits and not real OEM Glock parts. So you know, I really do like something that stick out a bit more than the stock Glock slide stop lever so I bought two Vickers Tactical units (Tango Down makes them) vs. reverting to OEM Glock 17 style levers.


This is the Vickers Tactical VTSS-01 “Tactical Slide Stop For Glock” up close.

Replacing The Lever

Always make sure your firearm is unloaded!!

So, I like to use a 5/32″ punch to push out the trigger housing pin while resting the pistol on a bench block. A bit of wiggling of the trigger can help it come out with relatively little force. You don’t need to beat it half to death. Some guys don’t use a hammer at all. I use one but with light taps.

Quick trivia for you – a 5/32″ punch is 3.9688mm – it works great to push out the pin and to help align things during reassembly. I have one of the Tekton Gunsmith punch sets and it’s very handy to have.
The new lever is installed and you can see the spring is captured under the top locking block pin. If the pin has been removed for whatever reason, install it first then the lever to capture the spring appropriately.
The lever definitely has more spring to it and stays down quite nicely now. I also like the subtle extension of the Vickers unit.
As you can see, it stick out just a tad bit more at the top and then angles down and back in. I definitely like the feel of it over a standard Glock 17 lever.

Problem Solved For the PF940CL

Well, that was that – problem solved. While I was at it, I decided to upgrade my Glock 34-style PF940V2 pistol as well. I was quite impressed by the Vickers unit and the G34 would lock open once in a while too so I figured why not?

When I inspected the G34, I found out that I had somehow not captured the spring at some point so that was the problem but I really liked the Vickers unit so I bought one and replaced it as well. By the way, I really think this was a real G34 slide stop lever as the finish looked right.

So, I did the same as the above except I did push out the locking block pin first to make it easier to pull out the errant spring. I then did the same as the above.

This is one of my favorite pistols! That Holosun HE507C-GR and Trijicon supressor-height sights are a great combination.

PF940V2 basedG34 on top and PF940CL G17/G19 hybrid on the bottom – both sporting the Vickers Tactical VTSS-001 Tactical Slide Stop Lever.

Great Video

I’m not a video kind of guy but I do realize sometimes a video can help a lot. I did some digging and Lenny Magill at Magill’s Glock Store has a great video that provides a lot of useful information about how to do the above and what to look out for.

In Conclusion

I’m happy the problem of randomly locking open is solved. I definitely like the Vickers unit and am happy to recommend it.


Note, I have to buy all of my parts – nothing here was paid for by sponsors, etc. I do make a small amount if you click on an ad and buy something but that is it. You’re getting my real opinion on stuff.

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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 and I have dealt with all of the one’s listed below and can vouch for them:

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