Glock slide stop won't lock the slide

harbl_the_cat

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I have some mags that have had a few hundred rounds through them. When I load and fire them dry, sometimes the slidestop won't lock.

First thing I did was give my G17 a good cleaning - no dice. I thought it may have been the ammo, since I shot some underpowered lead reloads through a Storm Creek barrel - but I changed to some 124 gn Combat Masters FMJ reloads and I still had the same problem. I have a few mags that are a little bit newer and I tried them out, and those DID lock the slide back. Doing so, I was able to identify which mags the problem happens with. I checked the follower on these mags and they don't appear to have any problems - if they are empty and I rack the slide back - they will lock the slide; it's only when I shoot them that the slide doesn't seem to lock. I also tried removing the slide, and just loaded the empty mag into the frame - and the slide lock did engage.

The only discernible difference I noticed was that the springs on the bum mags doesn't seem as heavy as the spring on some of the other mags. When I load the mags as well, the slide stop seems to cant outwards slightly.

Anyone know what else I can do to troubleshoot - besides getting more mags?
 
You're probably riding the slide release if it only happens when you're shooting. Happens to me all the time.

The hold-open tab on the follower can also break if dropped on something hard, but then that mag will not activate the slide lock at any time.
 
it's one of the two mentioned above. if it only happens with those old mags, change the springs. if it's random, it's you.
 
it's one of the two mentioned above. if it only happens with those old mags, change the springs. if it's random, it's you.

Exactly what i thought. Is your mags and slide stop are genuine Glock parts or some aftermarket ones?
 
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Its not the magazine springs. I'm still running the original three mags that came with my 17 nearly 7 years ago. The springs are the least likely culprit.

TDC
 
I'd bet it's your thumb riding the slide release. Like mentioned, shoot with the weak hand or only one hand and I bet it goes away.
 
Check your mags follower too...
I had some older style followers that had pieces broken off right where they're supposed to engage the slide stop...
 
All my mags are official GLOCK mags.

It appears to be happening repeatedly one 2 mags; but I agree my thumb could have been riding high on the frame. Could it also be bcause I might have left the mags fully charged for a prolonged period of time?
 
New magazine springs.

What? :) No way, you know how stiff Glock mag springs are.

Sime thing happens with my Brigadier 96. I don't mind it so much. I use the moment as a malfunction exercise. :)

I narrowed it down to a weakened recoil spring. I figure the gun is out of time, especially with hot loads, the slide bounces a bit if the recoil spring is weak. I actually install an extra power spring these days as I like to load on the hot side.

I'm pretty sure its the recoil spring causing this in my gun. I respring the whole gun when she starts and the problem goes away 'till another couple of thousand rounds downrange.
 
Could it also be bcause I might have left the mags fully charged for a prolonged period of time?

No. Springs do not deplete by being compressed for a long period of time. They weaken under repeated use.

New mags will soften up a bit, to a point and stop. They will take a set and function best when they do, but it will take an eternity to deplete a Glock mag spring I think.
 
You shoot so much you made the mag springs weak, wow. Maybe you should stop shooting so much or keep your thumb of the slide lock.

Went to the range today and actually spent a lot of time paying attention to positioning of my thumb. Indeed, that was the problem.

Can't believe I developed such a bad habit! That's going to be a tough one to break.
 
Went to the range today and actually spent a lot of time paying attention to positioning of my thumb. Indeed, that was the problem.

Can't believe I developed such a bad habit! That's going to be a tough one to break.

On the positive side you now know it wasn't a mechanical problem. Then again, we already knew that, it is a Glock.;)

TDC
 
Yup Yup. Although when it happened to me, it was because one particular mag follower was chipped off. So I did have to order another one. From lone wolf.
 
Yup Yup. Although when it happened to me, it was because one particular mag follower was chipped off. So I did have to order another one. From lone wolf.

Been there. Broke three followers. Mag still works, just won't lock open. Great for immediate action drills, bad for competing.

TDC
 
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