Glock issue with Zev firing pin safety

[cjsmith223]

So I bought the Zev firing pin safety and installed it today. I took the gun out to shoot it and started getting discharges off the reset. If I released the trigger slow it would fire, if fast it would function as normal. So I took the gun back in and tried to put the factory spring in with the aftermarket fps with the same problem. Replaced factory fps and spring and no more problems. Has anyone else had a problem with the Zev fps?

Thanks

CJ

[bountyhunter]

"I took the gun out to shoot it and started getting discharges off the reset. If I released the trigger slow it would fire"

Holy crap, that sounds dangerous.

I never tried the ZEV safety. Don't think it sounds like a good idea...

[bountyhunter]

The Glock trigger bar basically "rides" under the head of the firing pin safety plunger, the bump on the trigger bar lifts the plunger. I wonder if the ZEV plunger is longer so that as the trigger bar comes forward, it forces it down low enough that the tang on the trigger bar that holds the striker tab releases the striker.....

anyway, the main thing I don't like about Glock's design is the mickey mouse safeties. Probably not something to screw around with.

Did you take your calipers and do a comparison between the Glock safety and the ZEV to see where the diference is?

I would want to know just for curiosity.

Edited June 20, 2014 by bountyhunter

[rooster]

Explain " Mickey Mouse safeties". I thought glock was one of the safest pistols. Drop, safety, trigger safety, and firing pin safety. These things have been thrown off buildings, dragged behind cars, and thrown against walls. The op changed parts, and we also don't know what else has been done to the gun. He puts back in oem parts and gun works as designed. From this info we can assume it was the zev plunger.

[JackinSD]

I've had the exact same problem. I never did find a cure. I hope someone chimes in with a fix.

[bountyhunter]

Explain " Mickey Mouse safeties". I thought glock was one of the safest pistols.

It lacks one safety that every other major service weapon has: a firing pin blocking safety driven by a pivoting lever that resets on every shot as the slide moves out of battery. SIG, Beretta, Browning HP, Springfield XD and probably a bunch more I don't recall all use that type of safety. As the slide moves out of battery, the lever disengages and when the slide comes back into battery, it is automatically pushed forward and forced into a safe position where the gun's firing pin is blocked. Firing is impossible until the trigger is fully released and repulled so the trigger can re engage the lever which raises the firing pin safety out of the way, or discharge can not happen. That design is as close to foolproof as you can get for preventing the type of AD described in this thread as well as multiple fire events or going full auto as a result of a failure in the trigger group or bad gunsmithing.

The Glock firing pin safety is driven up by the bump on the top of trigger bar. When the gun fires, the slide pulls out of battery and it bumps the disconnector over which causes the trigger bar to pop into the UP position. Since the trigger is still held back as the slide comes back into battery, the tab on the trigger bar catches the tab on the striker as it is coming forward. That means as the slide comes into battery, the striker is fully pulled back (spring charged) and the firing pin safety is up out of the way of the striker (fire position). Any event allowing the striker tab to slip off the trigger bar tab results in discharge, as the event in this thread shows. This is the reason I think the Glock FP safety design is inferior to the type found in other service pistols. But since the Glock has no actual sear, it would be very difficult to do the other kind.

I thought glock was one of the safest pistols.

It would probably be safe to say that if only factory parts are used, and if all things are "in spec", then the pistol is safe enough. But as this thread shows, the safeties are not as good as some in terms of being forgiving when things are not exactly in spec or when something goes wrong.

Explain " Mickey Mouse safeties".

I am not a believer that three mediocre safeties add up to a good one.

I am particularly skeptical of the "trigger safety" that works right up until something touches the trigger.... and I realize the SA XD uses the same dumb safety. And the answer always is: safe gun handling requires the operator not touch the trigger until firing... so that safety is effective as long as nothing goes wrong and the user doesn't make a mistake. IMHO, that's not a safety like the safety on a 1911 or HP or Ber 92 which prevents firing when the operator accidentally does something wrong like holster it with his finger still on the trigger (the cause of Glock Leg). Just my opinion of what a useful safety should do.

And for the reasons I already stated, I think the Glock FP safety is an inferior design. Not necessarily dangerous, just not as good as others in use.

Edited June 20, 2014 by bountyhunter

[bountyhunter]

Explain " Mickey Mouse safeties". I thought glock was one of the safest pistols. Drop, safety, trigger safety, and firing pin safety. These things have been thrown off buildings, dragged behind cars, and thrown against walls.

As long as the trigger is forward and nothing is touching it, it would be very difficult to cause an AD. Glock AD's typically happen because of either user error or component failure/modification. But one thing any gunsmith does is understand the limitations of the design and that affects what can be done to improve performance. In the case of the Glock, you have to be VERY careful what you do to the trigger bar and striker to get a "better" release because unlike the other guns listed, you do not have the "backstop" of a safety that will prevent multiple fire events or AD fire events when something goes wrong as the slide bangs home into battery after discharge.

I don't know the exact cause of the firing in this gun (I suspect) but obviously there is some difference in the FP plunger that is causing it. It just makes me take note that an event this dangerous can occur if that one part is out of spec.

I mean holy crap, if I had a gun that fired when I released the trigger, that would scare the hell out of me.

Edited June 20, 2014 by bountyhunter

[rooster]

Bountyhunter, thanks for the informative reply, it really shed some light on how a glock safety works. I tried once to remove take up by using an aftermarket trigger assy. You know the kind with 2 set screws, I removed take-up but I also took away the drop safety. When I found out I went back to stock parts. I still have the over travel screw but every thing else is stock. Have you ever seen a glock AD because of the design of the safeties. I mean one that has not been altered trying to improve the trigger.

[bountyhunter]

Bountyhunter, thanks for the informative reply, it really shed some light on how a glock safety works. I tried once to remove take up by using an aftermarket trigger assy. You know the kind with 2 set screws, I removed take-up but I also took away the drop safety. When I found out I went back to stock parts. I still have the over travel screw but every thing else is stock. Have you ever seen a glock AD because of the design of the safeties. I mean one that has not been altered trying to improve the trigger.

I have never heard of an AD that was caused by the design of the Glock safeties (with factory parts). I assume the infamous Glock leg is the result of holstering with finger on trigger. With all stock parts (in spec) and everything right, the Glock safeties "work" as designed and the gun is reasonably safe. To keep perspective, it's probably "safer" than a revolver that has no safeties. But the Glock safety system is less effective at preventing NDs compared to a 1911 or HP or Ber 92 with the safety on which will not fire if the trigger is pulled with safety on.

Glocks are OK as long as the owner understands exactly what the safeties can do and can't do but as you noticed, I think most people don't realize that the drop in trigger kits can change things with only very subtle changes in parts. I think in that respect, the Glock is not very forgiving.

I'm still scratching my head that the OP got a gun that fires when you RELEASE the trigger just by changing the FP safety plunger. That would have scared me so bad I might have sold the gun...... I'd really like to understand the exact mechanism in play as to how that is causing the trigger bar to allow the striker to release.

[reptoid]

I highly suspect there are other issues with the OP's Glock that are just being brought to light by the new part. Assuming the FPS is the correct part for his model Glock, the minor differences that would exist between it and the stock part should in no way cause it to drop the striker during trigger return. Something else is very marginal, i.e. connector/trigger bar, or bad spring combination (striker/trigger). While the Glock mechanism looks very simple to the unfamiliar, the relationship between the trigger bar, connector, striker, and the two springs is very interdependant.

Bye the way:

Yes. I have used the Zev firing pin safety, as well as well as other aftermarket FPS's and the only malfunction I've ever seen related to them (in otherwise correctly set-up Glocks) were light strikes due to tolerance build up and the new FPS not quite clearing the striker in the up position.

Edited June 21, 2014 by reptoid

[rooster]

Reptoid, you bring to light a very good point. I don't know how an out of spec fps could cause this issue. The cruciform on the trigger bar has to be dropping away from the tab on the firing pin in order to let the firing pin move forward to fire the gun. That pluger could be too long, too short, but you have spring pressure pushing down so I think it would work no matter what. But if you had one of those trigger bars with the dip in it to help remove take up or if the set screw in of those trigger assemblies that let you adjust take up was adjusted too far then that would defeat the fps. But then he puts back in the oem fps and the gun works normally. Something else is amiss here.

[garp]

I had the same problem with a complete drop in Zev trigger some years back. It fired as you let the trigger reset. I removed the Zev and went back to the OME. The Zev got put a way and lost/forgot about after a divorce and moving. I had some other fellow shooters at the range with Zev and had no problems. I decided to retry shooting my Glock .40 in limited division, however, I could not find the Zev I had to compare with theirs. So I sucked it up, bought another complete Zev trigger package and put it in. Worked just fine.

Some time later, I found the first Zev I had forgotten about. I comparde that one to the new one. By just eye sight alone, it "appeared" to me that the part of the curcifix that rides on the stricker, did not have the same angle of bend as the new one I had bought. If you look at OME Glock trigger, they just ride on the leading edge of the stricker as you pull the trigger back, before they drop off the edge and let the stricker go forward to hit the primer. With the older Zev having a "flatter" profile, it was barely riding the edge of the striker.

With the older Zev trigger assemble, my assumption was, that with any moving mechanical parts, that when you add up all the slight moving wiggles as the parts are engaging, that it let the older, flatter Zev trigger "slip" off the stricker, thus causing a primer strike on "trigger reset."

I shot the the Glock most of all last year with the newer Zev and had no tigger resetting malfuntions. Since the curcifix is a stamped out part, my "assumption" is it just did not get made to the optimim tolareces.

Needlees to say, it was awesome being at the range trying out a new trigger and having a round go off on trigger reset. ( I won't admit it, but I think I peed my pants a little). It helps reinforce rule #2. Never let your muzzle cover anything you do not wish to destroy.

[bountyhunter]

Needlees to say, it was awesome being at the range trying out a new trigger and having a round go off on trigger reset. ( I won't admit it, but I think I peed my pants a little). It helps reinforce rule #2. Never let your muzzle cover anything you do not wish to destroy.

Amen

Edited August 20, 2014 by bountyhunter