I am no expert but you should not need to break in a GLOCK to make it reliable. The more you shoot it and dry fire practice with it the smoother the trigger should get but you shouldn't be dealing with the FTFs. Could be any number of things, starting with the ammo if you have eliminated the limp wristing. Since they are smaller grips, one thing that many people do is to add a Pierce grip extension on the magazine to give you a place for those other fingers. That will help with your grip going forward.

If the ammo isn't the deal, did you buy the G27 new? There are plenty of people here that will come along shortly to offer great advice on what to look out for or check on. Good luck and let us know how it goes!

Welcome to the forum as well, by the way.

That, or it may be installed incorrectly if someone took it apart to clean it and then re-assembled it wrong. I know as this happened to me just the other week. Everything looked good but the spring wasn't being compressed and it allowed the slide stop to rise up on it's own, locking the slide back.

OK. . .I just got back from the range. I put 220 rounds through it. I modified my grip to keep my right thumb out of the way better and everything seems OK for now. I did have it lock back twice early on in the session, but I believe I relaxed my grip discipline and my thumb may have hit it. After the second lock back, I fired another 180+ rounds without any problems. . . long story short, I think this failure was operator error. I would like to mention though that the slide lock lever does move extremely easy (compared to my G23), as if the spring was weaker. If I have the opportunity, I may have a Glock armorer evaluate the spring and maybe replace it just for giggles.

For those that are wondering, I am shooting Federal American Eagle 180 grain FMJ factory rounds for practice and Federal 165 grain HST Tactical JHP for self defense. My magazines (both) have the Pearce PG-2733 +1 extensions. I have noted that the JHPs have NEVER caused the slide to lock back--I'm not sure if it's coincidental or not.

Also, I purchased this gun new about a month ago from a Glock dealer in PA--it was test-fired at the Glock factory on 9/1/10

Thanks for all the comments and advice.

Rob

Not seeing your grip, you may want to try a more thumb forward grip. I don't have a G26/G27 yet but on my 19, my Left thumb is way down the frame towards the front sight, slightly pressing against the frame. In this configuration, there is no way my actual thumb could push up the slide stop. Let us know and stick around, the forum is great here as well are the people.

Originally Posted by rowemesp

When I first encountered this problem I thought it was improbable that I'd be hitting it with my thumb, but that "seems" to be the case, unless by modifying my grip I'm reducing the vertical movement that's causing the slide lock lever to move when the gun is fired. I think that modifying my grip could have cured a symptom, but didn't really cure the problem, which is why I'm probably gonna have that spring changed out when I can.

Has anyone ever heard of that spring being weak and letting that slide lock lever move when it's fired?

I haven't but again, it can be installed incorrectly. When re-installing my top pin, I didn't wiggle the slide lock back and forth and I was instructed to do. The spring ended up going over the top of the top pin instead of under it. In this configuration, there was much less compression on the spring. Almost no compression really. This allowed the slide stop to easily rise up and lock the slide back. I found out during dry fire practice. When racking the slide back, it would often lock back. I can only assume with all of the violent movement of a firearm firing a projectile, the slide lock would move more frequently than from dry firing.

One suggestion... check the slide lock mechanism installation. If the locking block pin is not installed prior to installation of the trigger bar (with locking block mechanism with spring depressed by the locking block pin) the slide will lock back randomly. Been there... done that!