Glock Slide-Lock Releasing Upon Mag Insertion

Greetings; new poster here! So, if this topic has been beaten to death in another thread, I apologize for the redundancy. (If such thread exists, I would appreciate it if one of you kind folks could steer me there.)

In my G19 Gen 5 (2000-3000 rounds thru at least), I recently changed out the stock guide rod and spring for a Tungsten set. Since then, when new mag is 'bumped in" while the action is locked open, the action often releases itself and slams closed into battery. Never happened before the swap-out, so that seems like a likely culprit. But this is simply not normal behavior for the gun (as one knows either from common sense or the owner’s manual) and I want to count on the gun always acting ‘normal’ – i.e., predictable.

I’ve heard from some folks that this is just what happens when you put some mileage on this gun. I’ve also considered the possibility that some gun oil or grease infected the contact point b/w the action and the slide-stop lever. Or, either the contact surface of the slide-lock (or the slide itself [hope not!]) has been worn down. If it’s the slide-lock, then it’s an easy and inexpensive replacement.

But bottom line is that I want to prevent this from happening, so I need to understand why it is happening in order to approach the problem. Any thoughts are more than welcome!

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Is there a gunsmith at your range or nearby who can take a look at it for you?

I’m with you-I want to know that my firearm is going to do exactly what it’s supposed to do!

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@Thomas153 Read the comments from GlockTalk Forum. Or as several stated “call Glock”.
P.S. I am not a Glock owner. :us:

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I can do this on purpose by putting my thumb on the slide stop and applying just a little downward pressure when inserting the mag. It shaves a little time when reloading from slide lock since you don’t have to rack to get back in action. Some Glocks are easier than others but I haven’t encountered one that wouldn’t.

So if you don’t want it to happen, make sure your thumb is clear when inserting the mag. If it still does it then I agree have a gunsmith look at it as just inertia shouldn’t be enough to release the slide.

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I consider that a feature. A Glock is not the only maker I can do that with. I also tend to slap the mags in, hard, to make triple sure they are seated. I can say though, even for me, it is not consistently 100%.

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Found these links on YouTube and they are very informative.

In general you should not be able to release the slide by slamming in a mag. If you can the gun is malfunctioning. After I am A$$uMEing that the mags are all one you have used previously with no issue. 3000+ rounds you may be in need of a “re spring”. That said you “changed” something.

Is your new recoil spring arching the slide away from the frame since it is stiffer? (I am a total noob to Glock’s but one of the first videos I saw was bending the FRAME, something about a pigs nose)

Has your mag release / spring become worn and the recoil spring is coincidental?

In general the slide lock lever is tight against the frame / slide interface and the action of driving in a mag SHOULD NOT engage it (mebby on an empty mag as the shelf is up) . I personally would address the issue so that it DOES NOT HAPPEN. I have seen too many young troops get used to slamming the mag and expecting the slide to go home on range guns and running into trouble in the real world both on pistols and rifle platforms.

On a totally different but related topic. Did the slide go home and the magazine fall out the bottom of the gun (or unseat) after the first round resulting in a Bang, Click scenario? That’s a whole different topic.

Cheers,

Craig6

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Hey, All–

Thanks for the input – a lot of good info!

Craig6, when this happens, the magazine stays fully locked in; it has never fallen back out.

Sounds like I need some further data via experimentation. Trouble there is that my range, in my opinion, is unsafe viz. COVID, so I haven’t felt good about going there.
(Then there’s also the issue of finding 9mm rounds for less than a dollar per shot!)

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Can’t make my old gen3 g19 drop automatically without slight pressure on the slide release. But wouldn’t mind if it did. I use the @Harvey method, though with the knuckle of my trigger finger since I am left handed. Speeds up my reloads noticeably. I practiced with snap caps until I could make it happen almost every time and make the move to rack the slide automatic on the rare times it doesn’t. Cheap way to practice and test in these ammo challenged times.

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OK, so I started by making the simplest and least costly attempt at a fix by ordering a new slide-stop lever. Problem solved. Looking at the old one now, I can see how it’s worn down. I’ve put probably no fewer than 4,000 rounds through the pipe, so that makes sense. A $16 fix after all those rounds amounts to an amortized replacement cost of $0.004/ round (40% of one cent). I’d say that’s a reasonable and cost-effective useful life for the original lever! And it turns out that I got the “extended lever.” I didn’t intend to get that one, and it’s not something I ever had much interest in. However, after using the new one for an hour or so (dry firing), I fell in love with it! You know how there are certain things that once you get one, you can’t remember how you lived without it? This is one; I have sweaty hands…

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Good for you!!! I don’t normally advocate throwing parts at a problem but then again you can’t know what “worn” looks like until you have “new” next to it. Yes extended things often make you wonder “Why didn’t I think of that?”

Cheers,

Craig6

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4k rounds through a Glock should definitely not wear any part in the firearm to the point of malfunction. That is a manufacturer’s defect. Not worth fighting with Glock about it, but let’s call a spade a spade for a change.

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Ken, I agree completely. And it’s one thing to replace a $20 part. It’s another thing entirely if you have to have the slide machined – or replaced altogether!

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