Glock slide failing to lock

[CadillacGolfer]

Hi folks,
have a Glock 17 gen 4 that just started to fail locking slide on empty mag. If I then manually pull the slide back, it will lock on the empty mag. What might I look to as to cause? I confirmed this on 3 out of the 5 mags I have for it. Was using Blazer Brass 115gr ammo

 

[kalash]

Same thing happened to me with a new-to-me 19 recently. After some Googling I'm pretty sure the problem was that I was accidentally holding down the slide lock with my thumbs-forward grip. That's all the advice I can offer

 

[CadillacGolfer]

Thanks kalash, but I doubt it, haven't changed my grip at all and have a couple of thousand rounds through it. I can confirm next time I hit the range by shooting one handed

 

[AM13]

Thanks kalash, but I doubt it, haven't changed my grip at all and have a couple of thousand rounds through it. I can confirm next time I hit the range by shooting one handed

What kalash said. I have the same problem with my SD9 if my thumb rides the slide it does that, but I didnt start till the gun got some use. Is it a new gun?

I left the range all pissed thinking the gun needed to be sent out for repair then it hit me on the ride home it was my thumb, went back to range next day and yup that was it. You gotta go make sure that's not it 1st

 

[Woop-woop]

Hi folks,
have a Glock 17 gen 4 that just started to fail locking slide on empty mag. If I then manually pull the slide back, it will lock on the empty mag. What might I look to as to cause? I confirmed this on 3 out of the 5 mags I have for it. Was using Blazer Brass 115gr ammo

Next time shoot it with just one hand, if the issue goes away then the cause is most likely your left hand hold the release down!

 

[Romokid]

I had a similar issue. The slide wound not stay locked back after the last round. Went to Four Seasons when the Glock armorer was suppose to be there. We tried manually pulling the slide back slowly on an empty mag and it would stay locked, but when you pull it real fast and let go (simulating last round fired) it would not stay back. We tried swapping out recoil springs and guide rods and a few other things out back until finally he swapped one of the trigger pins and bingo. Don't know why a trigger pin would cause it but it did. This was on a gen 1 G19.

 

[Greg Derr]

The slide lock is held in with a trigger pin, if the slide lock is pinched or rubs in the slot it will not move quickly to engage. Another option is that the mag spring is weak, not forcing up the slide lock fast enough at the gun cycles. If you remove the trigger pin and slide lock, test the fit of the slide lock with just the pin through it, it should be loose on the pin. Then try the lock in the frame without the trigger group, but the pin, it should move freely. Sometimes some plastic over mold can cause a bind, this can be shaved off with a sharp knife. The three out of five mags might also indicate weak mag springs, are they all new?

 

[Smokewagon]

Does it happen with all your mags? I've seen this on older mags (no ambi-cut) with old followers. Changed the follower, problem solved. If it happens on all your mags new and old, it isnt' a follower issue.

 

[7.62x39]

Are you using the slide stop as a slide release? I've seen slide stops wear to a point where they can cause a situation such as yours when being used as a release. Glock used to state explicitly not to use the stop as a release, sling shot only, but they seem to have backed off on that of late.

 

[CadillacGolfer]

Update: so, the thumbs have it. After a couple of different trips to the range to verify things, looks like after easily 5k rounds through it, I subtly shift my grip where my big sausage thumb was riding the slide release. Weird how my grip could shift like that without knowing it. Sorry for wasting your time fine NES folk

 

[Canndo]

Glad it's resolved. My Gen 4 G17 is quickly becoming my favorite! I'm running a Storm Lake barrel. It's a subtle but nice upgrade.

 

[AllaSnackbah]

glad you got it figured out OP.

on a side note, if you were to take the gun down for cleaning or something, then when you put it back together had the slide lock spring on the wrong side of the takedown pin, on the top side, i believe it would cause a similar issue.

 

[dcmdon]

To the OP. Try installing the medium backstrap. It might back your thumb up enough to fix the ergo problem.

 

[Kisspik002]

Same thing happened to me with a new-to-me 19 recently. After some Googling I'm pretty sure the problem was that I was accidentally holding down the slide lock with my thumbs-forward grip. That's all the advice I can offer

My 34 was doing the same thing, altered my thumb forward grip and made sure I didn't tap the slide release. Problem fixed. Best of luck

 

[dcmdon]

Well, I guess that's one of the few advantages of being left handed. Now let me tell you about how my thumbs push the slide stop out of a 1911 under recoil. Ugh.

 

[diesel112]

I was thinking accidental holding of release