[gbarber010]

First a little about myself, I'm a LE Officer, who has been carrying Glocks for about 18 years, G-19,23 and now G-22 Gen 4. I have also owned a G- 26, 27 in Gen 3.
I just bought a Glock 27 Gen 4 and have put about 125 rounds down range. In the last 50 rounds I have had a few failure to return to battery. They started in the last 3 mags shot. A few days ago, I shot about 25 rounds with 1 FTRTB in the 2nd to last mag.
I would like to hear from any other owners that may have experienced this action. When this has occurred it seems to be about 3/4 ways out of battery. All I need to do to get back in action is to pull back on the slide and release and all is fine. It has occurred with Federal Champion (a few), Federal HST (1) and Tula Ammo (1).
One observation I have is my 3 mags have strong springs and the 9th round is a bear to get in. So tight, I've been just carrying 8 rounds in the mags. This has not occurred after the first round fired from a mag.
Thanks in advance for any responses and I hope I have given enough infomation.

 

[gbarber010]

UPDATE I went by the shop where I purchased my G-27 from and they advised to check the mags. I went out and fired 30 rounds and the problem continued with all three mags. This time, I inspected the weapon more closely when the problem occurred and discovered that my slide catch was popping up during recoil and locking the slide back. That reminded me that I had an extended slide catch installed right before the problem started. I went back to that shop and they replaced the extended slide catch with a new one. I then went to my dept's range and fired 52 round through my G-27 with the 3 mags. All rounds ran flawless. The extended slide catch was a glock part. I assume the spring on the first one did not apply enough pressure to keep the recoil from causing it to pop up and catch. I'll have to keep an eye on this, but I think the old slide catch was the culprit.
Boy it feels good to have sweet running pistol.

 

[Glock Master]

Good news!

 

[gbarber010]

I compared the old extended slide cach with the new one installed today. Both looked the same to me. But, can't argue with the fact that it is now running fine with the replacement.

 

[semtexx]

Glad that you solved the problem. I've had my Gen4 27 for about 2 months now. She is completely stock and she runs perfectly. Bought it to be my CCW and I am 100% confident carrying it. The only thing that I plan on changing, are the stock sights to some Ameriglo hackathorn sights.

 

[gusbuster]

I was having that problem with my Gen4 G27, but in my case it was my thumb that was knocking the slide catch up during rapid fire. So I switched to a the old thumb locked down grip, and I haven't had any problems since.

 

[Glockrunner]

I was having that problem with my Gen4 G27, but in my case it was my thumb that was knocking the slide catch up during rapid fire. So I switched to a the old thumb locked down grip, and I haven't had any problems since.

Most likely the issue. OP sez he compared both the old and new slide locks and they are the same. A common problem with new stuff and the meat hooks...

 

[Bren]

Most likely the issue. OP sez he compared both the old and new slide locks and they are the same. A common problem with new stuff and the meat hooks...

Likely, but since the OP had also had a different slide stop installed, the guy who installed it may have put it in wrong, with the spring not under the pin, which is about the second most likely reason for the slide to lock back on a loaded mag. However, I didn't take the FTRTB to be the slide locking back - I have never seen the slide stop cause a problem, other than locking the slide back.

 

[Guntrainer]

The first thing I do to a Glock I have bought, if it has extended controls, is to replace them with the regular parts.

 

[Glockrunner]

Likely, but since the OP had also had a different slide stop installed, the guy who installed it may have put it in wrong, with the spring not under the pin, which is about the second most likely reason for the slide to lock back on a loaded mag. However, I didn't take the FTRTB to be the slide locking back - I have never seen the slide stop cause a problem, other than locking the slide back.

Exactly. The slide would lock back prematurely with that setup. Most likely his thumb was interfering with the slide or applying pressure on the extended slide release causing drag/friction on the slide. I doubt the first release was installed incorrectly.

 

[bentbiker]

Did anybody at the gun shop check to verify that the spring on the first extended slide stop lever was installed correctly -- under the locking block pin?

 

[Glockrunner]

Did anybody at the gun shop check to verify that the spring on the first extended slide stop lever was installed correctly -- under the locking block pin?

That would only cause the slide to lock open early. This wasn't the issue.

 

[gbarber010]

Just for info purposes, A glock armor inspected the weapon and the Slide stop was installed correctly. I'm left handed, so my thumb was not an issue. Also, I've been carrying Glocks for the last 18 years of my 23 year career as a police officer. I've also had the extended slide stops installed on my duty Glocks for some years now. I believe that it was a spring issue, but who knows. All I know is it working now and that what matters.

I do apolize for my first post. I should have paid more attention to what was going on. FTRTB was not a good discription of the problem, better would have been slide locking back.