Interesting Glock Problem

[CoryCop25]

I have a Gen3 17 that I purchase new in December 2011. I started using this as my main training pistol and I have about 4000 rounds through it. I am an armorer and has been properly maintained.
Lately I have been working with a different pistol for a specific LE purpose and I have basically put this G17 away for a bit.
Today, I brought this out and was doing some dry firing with it. Usually when I buy a new Glock, I will do some trigger work with it and smooth it out a bit and maybe add a Glock - connector. This gun had a nice trigger out of the box so I didn't mess with it that much.
The issue that I am having with it is quite strange. When I press the trigger and hold it to the rear, I cycle the slide and instead of resetting, the firing pin lets go. So I get a dead trigger. I removed the slide from the frame and visually inspected the parts. I followed the standard armorer's inspection procedure as demonstrated in the manual and everything checks out. This includes checking the connector to make sure it clicks into place and that the firing pin safety is in good operating order. I then put the armorer's orange back plate on the slide and the trigger bar has a perfect engagement with the firing pin. I also can see that when the firing pin lets go, the firing pin safety plunger catches the firing pin so if there was a round in the chamber, it would not go off.
I removed the internals inside the frame and there is a 336 ejector and the trigger return spring is intact and correctly installed. The connector has the proper bend in it.
I then replaced the connector with another standard connector and it continued to malfunction.
I then put the old connector in and replaced the trigger and trigger bar. The gun now functions normally. I then repeated the function check and everything checked out. The only concern that I have is that the old trigger bar has a dot on top near the cruciform and a little hook to keep the trigger return spring in. The one that I replaced it with has neither of these features. I can only assume that my parts may be a little older but never used.
The confusing part of this is; what caused this to happen while sitting in my safe? This pistol ran 100% every time I used it. And what part of the trigger bar is malfunctioning?

[platoonDaddy]

You solved your issue, mine was similar but replacing the trigger spring solved mine.
Gen 4 G17 with 15K rounds downrange, when disassembled it passes the following function safeties test using the Armorer's Manual page 17:

1. Trigger Safety

2. Firing Pin Safety

Noticed this issue when dry firing: I pull & hold the trigger, rack and then slowly release the trigger until I hear|feel the trigger reset. If I now release my finger from the trigger the Trigger Safety doesn't reset. If I put my finger behind the trigger and force to the front, the Safety will reset.

On the other hand if I dry fire, release the trigger and rack the Trigger Safety does reset.

[birdkiller]

Hello,
I had the same problem, and when the range armorers looked at it, they said that the parts had worn down to the softened metal (crappy polishing compound plus wear). The interface between the firing pin and trigger bar was not enough. I first found the problem when I switched out the connector.

I replaced the trigger and firing pin, no more problems.

So, its the interface between the back of the trigger bar and the firing pin. The metal is only surface hardened on these parts, so if you polish too much, you can wear through that outer hardened part, and through wear, the part gets out of spec. C

That's what my problem was, same symptom as yours, but who knows, it may be a different cause. Hope you get it figured out.

-Cole

[CoryCop25]

Hello,
I had the same problem, and when the range armorers looked at it, they said that the parts had worn down to the softened metal (crappy polishing compound plus wear). The interface between the firing pin and trigger bar was not enough. I first found the problem when I switched out the connector.

I replaced the trigger and firing pin, no more problems.

So, its the interface between the back of the trigger bar and the firing pin. The metal is only surface hardened on these parts, so if you polish too much, you can wear through that outer hardened part, and through wear, the part gets out of spec. C

That's what my problem was, same symptom as yours, but who knows, it may be a different cause. Hope you get it figured out.

-Cole

As I stated in my OP, the armorer's cover plate was installed and it had proper engagement (over 2/3). I am leading to believe that it is the area at the tail end of the trigger bar that engages the connector.
What really sucks is the original trigger pull that was really nice is now gone.

[birdkiller]

As I stated in my OP, the armorer's cover plate was installed and it had proper engagement (over 2/3). I am leading to believe that it is the area at the tail end of the trigger bar that engages the connector.
What really sucks is the original trigger pull that was really nice is now gone.

Oh sorry, I missed seeing that in the OP

[matemike]

I see where you checked all the functionality without actually firing it? But did you actually go fire it? Everything might've worked. I'm curious how the firing pin safety plunger appeared to be in good working order, but then it catches the firing pin when the trigger is pulled...? on an empty chamber. Is it not getting depressed all the way?

And to add my recent experience, I took out my 6 year old Gen 3 G19 trigger to give it a polish job according to grant's write up in a thread on here. The cruciform did not have a dot, but it was not smooth across the "cross" like pictured in grant's thread. It had deep stamp marks. Anyways, I polished it up and re-installed. Before doing any of this, I ordered a new (smooth) trigger and trigger bar just in case I messed anything up, and it's good to have spares anyways.

My new trigger arrived with the same deep stamp marks across the cruciform and an apparent dot as well. Plus, the trigger spring arm was bent a little to make a little wiggle back and forth. My original trigger bar has a straight trigger spring arm. Noticing all these differences, I went ahead and installed this new trigger to check fitment and functionality. All dry firing and re-racking with depressed trigger works flawlessly. I'll get to the range tomorrow or the next day. But I'll stay tuned here for more follow up.

[DBR]

Just a FYI:

I do not believe that the cruciform trigger bar parts are only surface hardened. I have tried to reform several trigger bars to get more striker engagement and the parts act like very hard spring steel. In fact if they are bent very much the part cracks. This is not a characteristic of case hardened steel.

The plating (Glock flavor of the month) is in fact only on the surface but since it often flakes of on its own I remove it on the contact surfaces.

[birdkiller]

DBR:

Good info. I'm just the guy that screwed up the trigger, not the people who were able to diagnose it. While I don't doubt what they said, I may have been interpreting it wrong. So, sorry if that's misinformation. If anyone has a definite answer to that I'll edit my first post.


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[T2C]

It's odd that the issue turned up when it did. I can see how the timing would make someone suspect that storage would be related, but it just might be coincidence that this happened when it did.

Did you check the angle of the engagement area at the rear of the cruciform on the malfunctioning trigger mechanism and compare it to the working unit?

Did the pistol have the New York Trigger Spring in it at any time?

Did you check the firing pin channel liner to firing pin spring fit for looseness?

[CoryCop25]

I'm curious how the firing pin safety plunger appeared to be in good working order, but then it catches the firing pin when the trigger is pulled...? on an empty chamber.

When I was referring to the safety plunger, I meant that it was working. The firing pin was releasing prematurely and the plunger was doing what it was supposed to.