# Glock 34 jamming problems



## martial_field (Oct 16, 2006)

Recently, my G 34 has been jamming frequently. Every 3rd round on average. I have no idea what is going on. I have used different types of factory ammo, different magazines, keep the gun clean. Started about two weeks ago. Does Glock cover this type of problem from the warranty or must I go to a gunsmith on my own money? :smt022


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## nukehayes (Sep 22, 2006)

approx. how many rounds have been through the gun? Have you replaced anything with aftermarket parts? Also have you detail stripped it and checked for anything loose or broken parts? I don't know what's wrong.


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## Shipwreck (Jan 26, 2006)

Check your extractor and ejector.

Yes, If U send it to Glock, they will fix it free. But, with the shipping cost, U man wanna have a certified Glock armoror look at it if U can find on locally.


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## martial_field (Oct 16, 2006)

Over 10000 rds thru gun. I replaced the recoil spring to see if that was the problem. Still jammed with the new recoil spring. I have not replaced any parts with aftermarket parts although I did try to put in an after market uncaptured recoil rod and spring. I replaced that set up with the factory recoils rod and spring after it started jamming. I have not replaced the extractor or ejector. The parts seem to look normal. I'm at a loss to explain this problem. 

I think I will e mail some local Glock armorers and wee what they suggest. Thanks for the input.


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## martial_field (Oct 16, 2006)

The jams are failure to feed where the slide locks back as though it were the last round fired in a mag.


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## DJ Niner (Oct 3, 2006)

If the slide is being prematurely locked to the rear by the slide stop lever (the same part that normally locks it back when the last round is fired), then it's probably one of three causes: improper assembly, broken slide stop spring, or operator grip/thumb placement problem.

Improper assembly: If the frame has been stripped and the slide stop lever removed, it's important to make sure the lever is installed with the leg of the spring UNDER the locking block pin, not OVER it. This is a common error during reassembly, and often the gun will function check properly, but when fired the out-of-position spring will fail to keep the slide stop in the down position until the mag follower raises it after the last shot. This can cause intermittent lock-backs as the gun is fired. Corrective action is to inspect the spring and make sure it was not bent/damaged, and if okay, reinstall it correctly, with the spring's leg UNDER the locking block pin, so the slide stop lever has strong spring pressure downward. To check it, pull up on it slightly, let it go, it should SNAP downward.

Broken spring: If the slide stop spring has been bent, broken, or lost, you will need a new slide stop (as the spring is attached to it). They are not expensive, and can be user-installed if proper disassembly/reassembly procedures are followed. As a matter of fact, the most common cause of a damaged or broken spring is assembling the weapon in a different order than presented in the manual. If the slide stop lever is installed BEFORE the locking block pin, the pin will hit the spring leg as it is inserted, and then the user usually gets out a hammer and attempts to DRIVE the pin in, THROUGH the spring leg, bending or breaking it.

Operator problem: If the lever and spring look okay and are installed properly, then it's probably a shooter-induced problem. Many shooters with medium-to-large hands will inadvertently rest their shooting hand thumb on or under the slide stop lever when shooting, and under recoil, the thumb will accidentally raise/activate the slide stop, locking the slide to the rear even though there are still rounds left in the magazine. Yes, I know, that's impossible, your thumb is nowhere near the lever; I said the same thing, until I found out I was doing it, too. Most folks will SWEAR they are nowhere near it, until they do the "test"; just shoot one or two mags of ammo with the thumb completely off and away from the lever and that part of the frame. Point it up, point it outward, curl it WAAAAAAY down, it doesn't matter; just make absolutely sure your thum is at LEAST 1 inch away from the lever at the moment of firing. If your problem was cropping-up every 3 shots or so, and you shoot two mags and it doesn't do it at all; well, we've located the problem, haven't we? Don't be embarrassed; it's very common, not only with Glocks, but with SIGs, too (I had a friend who did it with his new Beretta 92; drove him crazy until he figured it out).

Hope this was helpful. Let us know what you find out.


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## martial_field (Oct 16, 2006)

Thanks, Niner, very good information. I have installed the slide stop lever correctly, making sure the spring is under the top pin. However, I noticed that the spring is a little weak in comparison with my slide stop spring on my Glock 35 so I am ordering a couple of replacements to see if that corrects the problem. 

It could be my grip as well. I have changed my grip recently so that my two thumbs are not touching the gun (after reading Brian Enos' book-trying to achieve more neutrality in my grip). Possibly, I have positioned my right thumb too low so it is riding up on the slide stop lever in recoil and I just didn't realize it. I will try some different grips on my next range trip to see if making sure my thumb is higher solves the problem. 

Anyway, I found your post very informative and helpful. Thanks for taking the time to compose it.


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## Glockamania® (Dec 21, 2006)

DJ Niner got a bull's eye.

Martial-Let us know what you find out.


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## martial_field (Oct 16, 2006)

I'll do that. My next range trip will probably be some time next week. I have a competition this Saturday but I'll take my CZ in case I don't get the problem solved with my G 34. 

In rereading my last post, I wanted to make it clear that I had been installing the slide lock and spring correctly all along. But it was the other two possibilities that may well be causing the problem - ie., a weak slide lock spring or my thumb inadvertently hitting the slide stop lever in recoil. Funny thing is I was thinking about my jamming issue all last night after I posted my problem and I began thinking it must have something to do with the slide stop lever to explain the specific way the gun was jamming. I did not have the knowledge base that Niner has nor did I have my thinking systematized as he did. That's why his post was so helpful.


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## PP914 (Jan 7, 2007)

Since you have ruled out inproper Slide Stop Lever installation, it's down to your grip or a damaged Slide Stop Lever. Post up when you get back from the range.


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## martial_field (Oct 16, 2006)

I made a trip to the range today, put about 200 rds through my G 34 and 100 through my G 35 with no jamming problems. The cause was my grip. In an attempt to achieve more "neutrality" in my grip ( a la Brian Enos), I was letting my right thumb slip under the slide lock lever and when the gun recoiled, the thumb was contacting the lever causing the gun to go into slide lock. When I changed the position of my thumb, no more jams. 
At first, I tried "riding" the slide lock lever from the top as I do with 1911s with the safety. I like this technique with 1911s because it allows me to get the highest possible grip on the gun and I don't have to change the position of my right thumb after disengaging the safety. However, with the Glock, while I didn't have any more jams, the gun does not go into slide lock, as it should, when the last round in the magazine has been fired. So, I placed my thumb in its old position, in the groove below the slide lock lever and I placed enough pressure on the thumb so it would not slide up during recoil. 

Anyway, thanks to DJ Niner for pointing out the most lilely causes of the jams.


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## DJ Niner (Oct 3, 2006)

Glad I could be of some assistance.

Good luck with the technique adjustments; I know it can be frustrating! :smt023


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## fattsgalore (Jan 20, 2007)

Since it was you and not the Glock this thread has to be burned to keep up Glocks reputable name. I saw the words Glock and Jam. 
To be honest I gasped. I hear about Glocks blowing up but not jamming.


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## Vom Kriege (May 5, 2006)

With that high of a round count, it wouldn't be a bad idea to replace the extractor, ejector, and the plungers and springs.


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