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G30S Slide Not Locking Back

768 views 12 replies 10 participants last post by  Dennis Wallace  
#1 ·
After 15 or so 100%-reliable Glocks over more than twice as many years, I now have a G30S that is refusing to lock back after the last shot on about a 50-50 basis, regardless of ammunition, swapping magazines (both 30 and 21 models), etc. I have been trying to troubleshoot every possible problem, and that has included disassembling several magazines, cleaning them, etc. I replaced springs and followers in a couple of them as well, still no improvement.

Oddly enough, one of the magazines that came with the gun is 100% reliable to lock the slide back, whether racking it manually or shooting. But the second mag that came with it is not even close to being consistent. They look identical in every way.

When the slide is off the frame, and an empty mag is inserted, every one of them causes the slide stop lever to raise up, to what appears to be a reasonable height that should lock it back. But again, only one magazine seems to be working consistently, with the others being very hit-or-miss.

Full disclosure: this problem started with the original factory part installed. I have always like the extended levers, and thought that installing one might remedy the problem. (I've made sure that the spring for the slide lock lever is correctly positioned under the trigger bar.) I have done this on almost every other Glock I've owned, with no problems whatsoever. But the new lever did nothing to alleviate the problem.

There are competent gunsmiths in my area - have been trying to solve this myself, and thought I would try by getting some input here before I go that route. Thanks.
 
#3 · (Edited)
Here are some things to check out:

From Glock Armorer's Manual:


Observed Problem: Slide fails to lock open on last round

Probable Causes:
  1. Magazine follower broken
  2. Weak magazine spring
  3. Dirty magazine
  4. Dirty gun
  5. Needs lubrication
  6. Worn slide stop lever notch
  7. Deformed magazine
  8. Trigger pin inserted too far (left or right)/slide stop lever worn
  9. Slide stop lever worn/damaged
  10. Underpowered ammunition
  11. Shooting with an unlocked wrist
  12. Improper grip
These are not exclusive. At least a good place to start "trouble-shooting".

Comment: your narrative indicates that you have eliminated some of the above. However, I wanted to give you the list that an Armorer would check out.

Let us know if you find the cause. Best of luck.

ETA: after I read your profile, I noticed this -

Image

Thus, the above information is already available to you. Sorry for the repeat.
 
#4 ·
I will guess you are right handed, use a high grip, and this is your first subcompact size Glock.
The thumb is a common culprit, unless you have fully disassembled the gun- in which case it was a faulty re- assembly of the slide stop lever and spring.

Are these factory mags? Look at the step on the follower, to see if it is pushing up the lever.
 
#5 ·
If all followers are raising the slide stop with the slide off the frame, replace the mag springs- and you might as well replace the followers while you're at it.

I am not a fan of extended slide locks, because it's more real estate for a finger to find under recoil.
 
#7 ·
I have same problem with my 30s. Maybe 100 rounds through it. All 3 are Glock mags.
If I pull the slide back, let it catch, then lay it down very carefully, it may set there 2 to 5 seconds then snap closed. Using empty mags.
when it was new it would hold back but after a couple mags through it started to fail. Msgs are clean as well as the 30s. One of the mags is new. Never used at range. Very perplexing.
 
#9 ·
I have same problem with my 30s. Maybe 100 rounds through it. All 3 are Glock mags.
If I pull the slide back, let it catch, then lay it down very carefully, it may set there 2 to 5 seconds then snap closed. Using empty mags.
when it was new it would hold back but after a couple mags through it started to fail. Msgs are clean as well as the 30s. One of the mags is new. Never used at range. Very perplexing.
I've had that same experience as well with the delayed snap closing. If it DOES lock back, it's often only temporary. This is the first experience I've ever had with a Glock not functioning 100%, and it's unnerving. Especially since the 30S seems to fit my hand perfectly, and I really do want to have it as my EDC.
 
#11 ·
Is there any solution found for this? I have 15 or so Glock 21 and Glock 30 magazines and only two lock the slide back. I sent it back to Glock and they replaced all the easy parts (slide stop, extractor, firing pin etc). I tried swapping everything around the slides and frames with the two other G30sf models I have and the only common denominator is the 30S slide, it does it with the other lower frames as well.
I am also losing a lot of confidence in Glock.
If anyone figured it out please share.
 
#12 ·
I have a G30S that's probably right at 10 years old. The things is a Swiss watch. No issues! I'm wondering if they have changed something in the design of the slide or the newer magazines.