Glock Slide Problem


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JoeMal
June 30, 2010, 08:20 PM
I was out at the range today with my G17 and the slide was not locking back after the last round was fired. I shot maybe 10 magazines and it happened 9 out of 10 times (2 separate mags). This has never happened before. Is there a cause for this? Like I said I've shot thousands of rounds with this gun before without any problems...so a bump in the road like today has me...wondering...:eek: :uhoh: Any thoughts?

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Strahley
June 30, 2010, 08:24 PM
Could be a number of things

-weak magazine springs
-different grip, you might be hitting the release
-spring for the release may not be installed correctly
-etc

When was the last time you detail cleaned it?

JoeMal
June 30, 2010, 08:28 PM
-Would it be a huge coincidence that both mags started acting up on the same day? How would I test this...other than buying more mags?
-I doubt it's my grip...I feel like I hold the gun the same every time...though I suppose it could be
-Last detail clean was a few hundred rounds ago...maybe 300-400 rounds ago? I've shot several times since the detail clean without problems

Shawn Dodson
June 30, 2010, 08:39 PM
From a gunfighting perspective, this is one reason to put your slide in battery BEFORE you load your pistol to train yourself to apply the extra force required to seat the magazine when the slide is not locked open, such as what happened in the OP's situation or when you seat a fresh magazine after clearing a doublefeed.

I use the tasks of loading and unloading as a training opportunity to exercise the same skills I have to use to clear stoppages. When I load my Glock 19 I always put the slide in battery before I install a loaded magazine. After I seat the magazine I roll the pistol to the right about 90-degrees while simultaneously racking the slide to chamber a cartridge. Then I perform a Tactical Reload.

JoeMal
June 30, 2010, 08:59 PM
this is one reason to put your slide in battery BEFORE you load your pistol to train yourself to apply the extra force required to seat the magazine when the slide is not locked open, such as what happened in the OP's situation or when you seat a fresh magazine after clearing a doublefeed.Pardon? Are you giving me random tips? Because I'm not sure what this has to do with my issue.

Extra force required to seat the mag when the slide isn't locked open? My Glock doesn't require 'extra force' to do anything. The mag is either in or out....no Superhuman strength needed. Care to elaborate anymore?

Shawn Dodson
June 30, 2010, 09:21 PM
Care to elaborate anymore? When the slide is in battery the top cartridge in the magazine makes physical contact with the bottom of the slide. When you seat the magazine the top cartridge is pushed farther into the magazine against the resistance of the magazine spring.

When the slide is locked open you do not encounter this resistance.

In a defensive shooting, if you shoot your gun dry and the slide fails to automatically lock open or you had to clear a doublefeed, then the slide will be in battery and you will have to exert more effort to seat the magazine to recover from this situation.

chicharrones
June 30, 2010, 09:28 PM
When the slide is in battery the top cartridge in the magazine makes physical contact with the bottom of the slide. When you seat the magazine the top cartridge is pushed farther into the magazine against the resistance of the magazine spring.

When the slide is locked open you do not encounter this resistance.

You're right. Especially noticeable on a full magazine, not as noticeable if only filled half way or so.

W.E.G.
June 30, 2010, 09:45 PM
what kind of ammo?

JoeMal
June 30, 2010, 09:48 PM
what kind of ammo? S&B. But I've shot hundreds of rounds of this stuff without problems

Strahley
June 30, 2010, 09:58 PM
If you insert an empty mag and manually rack the slide, will it lock back?

JoeMal
June 30, 2010, 10:05 PM
If you insert an empty mag and manually rack the slide, will it lock back? Yes. Every time. I can close the slide with an empty mag in the gun, dry fire, and rack the slide and it will stay open every time.

Shawn Dodson
June 30, 2010, 10:09 PM
The front left corner of the magazine follower, under magazine spring pressure, engages the slide lock when the last shot is fired.

I suggest you inspect your magazines to verify the front left corner of the magazine follower is undamaged. (There is a molded notch on the front left corner of the follower. There may be a number imprinted on the floor of the notch.) You can damage this area if you slam an empty magazine home.

With gun unloaded and the slide locked open insert an empty magazine. Just before it seats look through the ejection port to see where the internal "tab" on the slide lock engages the notch on the follower. After you seat the magazine, release the slide lock to put the slide in battery then slowly retract the slide, and while looking through the ejection port, observe the interface between the magazine follower and the slide lock tab for proper operation.

You mentioned the problem occurred with two magazines. Are these the only magazine you have? Have you cleaned them? If not there might be enough grime in the magazine tube to retard the movement of the follower and it either moves up too slowly to engage the slide lock before the slide is propelled into battery by the recoil spring, or the follower could be seizing in the magazine body.

Good luck.

JoeMal
June 30, 2010, 10:27 PM
Shawn Dodson

Here are some pictures showing my mags. I can see the '9' on both followers and there really isn't anything that looks like damage to me. Both have some cuts/jabs/small nicks in them, but I assume that's from normal wear. Nothing seems exaggerated or obvious. The position of the internal tab in relation to the follower looks the same to me after inserting a mag with the slide open and when I slowly open the slide.

Yes, these are my only 2 mags. No, I have not cleaned them. I don't know how to 'clean a magazine'. The exteriors aren't dirty; I wipe the frame and tops with a white cloth and it comes out clean. Like I said I'm not sure how to clean the inside....

http://i161.photobucket.com/albums/t232/jomal206/30dd23a2.jpg

http://i161.photobucket.com/albums/t232/jomal206/1be40f9d.jpg

http://i161.photobucket.com/albums/t232/jomal206/a43c21cb.jpg

Runningman
June 30, 2010, 11:27 PM
Is this one brand and type of ammo?

Could it be a weak lot of ammo? Years ago when working up some 115 Gr handhoads for my G17. I found that a certain charge was enough to cycle the slide that it shot fine. But as it turned out it was slightly short stoking the slide just enough that it was not locking the slide back on the last round. Going up just .2 of a grain cured the problem.

The longer heaver slides of the G17 and G34 seem a little more prone to this issue especially with weaker 115 Gr loads.

JoeMal
June 30, 2010, 11:31 PM
Runningman

I was shooting Sellier and Bellot ammo. I have shot hundreds of rounds of this ammo (bought 1k last year) without any problems like this. Read the whole thread and you will get the details...

BearAZ737
June 30, 2010, 11:34 PM
Do you have big hands? And point your thumbs forward? Because that might cause you to hold the slide release down after you shoot your last round. Happens to me once in awhile.

lions
June 30, 2010, 11:36 PM
S&B. But I've shot hundreds of rounds of this stuff without problems

I'll echo Runningman, have you shot this particular box of ammo without incident before? I would pick up a different brand of ammo and run it through your gun just to pinpoint or eliminate ammo as a problem.

Edit: Nevermind, not too quick on the draw tonight.
I have shot hundreds of rounds of this ammo (bought 1k last year)

bds
July 1, 2010, 12:54 AM
JoeMal, if the slide locks back when you manually rack the slide with the empty magazine inserted (meaning your magazine springs have enough tension) and if the slide does not lock back when a round is fired, then it's:

1) Slide is not moving back enough when the last round if fired for the magazine follower to push up on the slide lock
2) There's obstruction/roughness towards the top of the magazine tube (inside) that is hanging up the magazine follower to move all the way to the top when the last round is fired.
-----------------------------------
1) Since you are shooting the same ammunition that you shot in the past, can you verify that you have the same lot number of bullets? If you have more than one production lot in your 1000 round purchase, it may explain the difference in bullet performance. Are you are able to borrow or use the range rental Glock magazines? If the slide not locking is repeated with other Glock magazines, then it may be the ammunition lot. If the problem goes away with other magazines, then the problem is with your magazines.

2) Take apart your magazines and inspect the inside of the magazine tubes for any debri or roughness near the top of the magazine that might hang up the magazine followers. If the magazine parts are serviceable, clean and reassemble. If you think the magazine spring tension is weak, you can test this by adding cut pieces of cardboard to the base of one of the magazine (3 or 4 layers below the spring) to increase the tension. If the magazine with cardboard pieces locks the slide but the other magazine won't, then you need to replace the springs.

Al Thompson
July 1, 2010, 08:05 AM
Magazines look fine, ammo as well.

I've seen this a couple of times.. Get someone to watch your thumbs when you shoot. I think your riding the slide stop a bit and that's the hang up. :)

Shawn Dodson
July 1, 2010, 08:16 AM
Remove the slide and clean the slide lock as well as the area around it, both internally and externally. There could be some grime that's retarding its movement. Because you're experiencing problems with both magazines I suspect the problem to be here.

Your magazines, although showing some wear, appear serviceable.

Here's a YouTube video with Lenny Magill demonstrating how to disassemble/assemble a Glock magazine: http://www.youtube.com/watch?v=uB28dFAMVQc

JoeMal
July 1, 2010, 08:16 AM
Thank you all for your help. I will try a few of the testing methods that have been outlined and will follow-up. I have plans to go to the range on Saturday.

Nuke8401
July 1, 2010, 08:50 AM
After putting at least 10,000 rounds through a Glock 34 I have learned some things:
1. With good ammo the gun will function as designed if you put it together correctly.
2. With good ammo the gun will function as designed even if you think you are a gunsmith and change some things.
3. With good ammo and not riding the slide stop/release the slide will always lock open.

My suggestions:

1. Buy/try a new box of ammo, name brand, yes I know you have shot XXX rounds of the S&B, just make it easy and eliminate the ammo as an issue.

2. Shoot it left handed only, this will tell you if you’re riding the slide stop/release.

The "insert mag on a closed slide" discussion was interesting though having nothing to do with this OPs question.

My definition of interesting in this case = one mans opinion.

But then again, all this free advice, including mine, could be worth exactly what you are paying for it.

DustyVermonter
July 1, 2010, 09:00 AM
I would say load up a round of heavier bullet into the mag first and see if it locks the slide back, when I shoot 115gr UMC my glock short strokes a little and even though you say it isn't the ammo, I think it really is. Your magezines are fine.

JoeMal
July 1, 2010, 09:01 AM
Thanks, Nuke, too. I am going to look into my grip. Initially I didn't think that was the problem but the more hear it come up the more I think it could be the problem. Shooting left handed is a great idea.

TechBrute
July 1, 2010, 09:24 AM
Regarding the mags, they may or may not be the problem here, but you seem to be averse to buying new mags. Mags wear out, just adjust to that fact. Glock mags are under $25.

ny32182
July 1, 2010, 09:27 AM
If you haven't cleaned the inside of the mag tubes in thousands of rounds I would do that anyway. There are a limited number of things that could be causing this and you can easily eliminate them one by one.

-Pull the springs and followers out of the mags, wipe crud out of the inside of the tubes and off the sides of the followers. This will make sure your follower is moving freely; and it needs to do so to consistently lock open when shooting. It doesn't have to move as fast to lock open when manually retracting the slide as it does when shooting since the slide velocities are very different in those two situations. I don't think you've entirely eliminated this as a possible cause before cleaning the mags.

-Crud could be obstructing movement of the slide catch. Easy enough to see if it is moving freely with the slide off. Take the slide off, move it with your finger; pop in an empty mag and make sure it is moving... etc.

-Ammo: if nothing above works, change it for ****s and giggles. This probably isn't it, but can't come off the list until you've proven it is fine.

-Grip: The most common cause of both failures to lock open and slides locking open with rounds left in the mag. I've seen plenty of both. Shoot it left handed, let your buddy shoot it... etc. Even if you don't think your thumb is riding the catch to keep it down, it may not be obvious while actually firing.

-Worn slide catch lever? The most I've got on one is about 4k rounds; I don't know if the end that engages the notch in the slide can become worn to the point where it doesn't catch well, so that is just speculation; I would replace that part and the spring if all else really failed.

W.E.G.
July 1, 2010, 09:33 AM
Detail strip, clean, and lubricate.

Nuke8401
July 1, 2010, 10:52 AM
My experience with Glock mag wear/problems.
1 G34
4 factory hicap mags
5 years/>10,000 of rounds competing in IDPA and practicing.
Same mags, mag springs, followers. I have disassembled them and cleaned them twice in that time.
My conservative round count is based on buying 4,000 cases (x3) from THR members and reloading all once and about half twice.


My confidence is in factory Glock mags. I did try a Korean mag once, still have it sitting in a box someplace, slide wouldn't lock back with it.

In that time my Glock malfunctioned one time, and of course it was my fault, I installed the slide release/stop spring on the wrong side of the upper pin which normally results in unwanted lock open condition.

Al Thompson
July 1, 2010, 12:08 PM
Shoot it left handed only

Nuke, that was brilliant. It's going into my play book! Thanks! :D

labhound
July 1, 2010, 01:17 PM
I had the same thing happen to me yesterday while shooting my Beretta 92FS and my Stoeger Cougar. The slide on both guns at times would not stay locked back after the last round was fired. I finally realized it was the new thumbs forward grip I was using. Both thumbs were hitting the slide stop and keeping the slide from locking open after the last round was fired. I'll either have to change my grip or remember to change it on the last round! This might be what your problem is!

REAPER4206969
July 1, 2010, 03:00 PM
Limpwrist.

Runningman
July 1, 2010, 05:51 PM
QUOTE]I was shooting Sellier and Bellot ammo. I have shot hundreds of rounds of this ammo (bought 1k last year) without any problems like this. Read the whole thread and you will get the details... [/QUOTE]

I did..... and what caught my attention is this-Last detail clean was a few hundred rounds ago...maybe 300-400 rounds ago? I've shot several times since the detail clean without problems The Power factor requirement go up slightly with a dirty semi auto pistol as the slide becomes a little sluggish in cycling.

All this is assuming you are not limpwristing or riding the slide stop.

Nuke8401
July 1, 2010, 07:51 PM
I have gone over 2000 rounds without cleaning, no problems. I shoot factory and handloads that make 130=135 PF (soft loads) for IDPA, no problems with a dirty Glock.

Glocks aren't like most guns, see the link for the Glock torture test.

http://www.theprepared.com/index.php?option=com_content&task=view&id=90

Al Thompson
July 1, 2010, 07:55 PM
IME, limp wristing tends to be evident by FTE and sometimes double feeds. Never seen slide lock as an issue with that problem.

GLOOB
July 2, 2010, 03:48 AM
It wouldn't be a huge coincidence for both mags to go wonky at the same time. I assume they're your only mags, and you use them both when at the range? And just because the slide locks back when racked manually certainly doesn't mean the ammo has to be the problem.

I'm going to guess if you buy new mag springs, problem is solved. They're 6 bucks each, so you might as well order them. Cleaning the mags might also solve the problem. But buying new springs will keep them going for longer till your next maintenance.

Nuke8401
July 7, 2010, 07:03 AM
NY,

Whats the verdict?

JoeMal
July 7, 2010, 07:47 AM
I think the problem was with my grip, but I didn't get as much of a chance to test as I had hoped. I did get a bit of range time in, but we were shooting my .22 more than anything. I'm going to do some more investigating next time I'm out...thanks for checking back

jonboynumba1
July 7, 2010, 10:31 AM
Most often that is caused by weak mag springs or excessively worn followers (with glock it's usually a weak spring and an OLD OLD magazine) Yours look almost new. If they stay loaded at 17 rounds all the time and are more than a year old it's still possible some new springs would help....more likely in your case it's either operator error (IE hitting or holding the release down with one of you thumbs without realizing it) or your mag catch itself is broken, warped/bent or incorrectly installed. Incorrectly installed usually locks the gun open when it shouldn't be rather than failure to lock open...so that narrows it down to two options operator error or you need a new slide stop...a stock one is $7-9 if you have an extended on in the gun ($17) take it out and go back to the factory one and I bet the problem goes away...if you have the factory one for $7 you may as well swap it as it's cheaper than multiple mag springs...of course you'll want spare mag springs anyway at some point so you may as well order both and see which one fixes it. If it's operator induced you just got some spares....no big deal...you'll eventually use them.

nebula
July 30, 2010, 06:07 PM
I have a Glock 19 and this happened on the very first magazine i fired. I was a bit perplexed...shot another magazine...that time it locked back. I observed my grip a little more closely and it became quite clear that I was riding the release and not even realizing it. I use a very common thumbs forward grip like many IDPA shooters. I adjusted my grip slightly and it never happened again.

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