How to get rid of the infamous CZ/VZ gremlin

[Xman]

This is a home made, free, easy to do fix that can be accomplished in a few minutes. I have done this myself and I have gone from one failure to #### the trigger every 10-20 rounds, to zero failures in a trial of 200 rounds.

The tools you will need:

Table vice, file, tape measure and fine sand paper.

First of all let me tell you how I came to think of this. After reading all the "gremlin" threads on here I came to the conclusion that Obiwanbonjovi was right about what is causing the problem:

"From what I have read all over this page it seems the general belief is that the gremlin is caused by the bolt carrier failing to disconnect the trigger. Until today that was my understanding. Wrong, the carriers seem to disconnect trigger every time.

The problem is caused by the striker re-connecting trigger, by forcing the sear down too far during its rearward travel.

A few other fixes were suggested by some but they seemed unnecessarily complicated to me. If the striker nose forces the sear too far down during its rearward travel, the simplest solution seemed to be shortening the striker nose a tiny bit, so that when it pushes down the sear, it pushes it less distance, equal to the amount of material (nose length) removed.

So, I took the striker, put it in a vice, (wrapped in cloth to protect it while being squeezed by the vice) and filed down about 1/32; that will probably be enough.
Any more than that and you are risking other kinds of failures.

When you do this, make sure you maintain the same slope as before and make sure you do it straight.

When you've filed as much as you want, take some very fine sand paper to the filed area and smooth it out so that there are no burrs or protruding surfaces, however small. This way the striker nose pushes on the sear equally at all points of contact.

Here is a picture of it, although the words are self explanatory:

The area indicated by the orange pointer is the striker nose and that's what you file down.

As I mentioned before, after doing the mod to the striker, I went to the range with the rifle and an extra, unmodified striker.

I tried both. The filed one so far has produced no further failures in 200 rounds which were shot in all possible ways.

After I put the unmodified striker back in, I got repeated failures again, within the first 20 rounds.

I hope this works for you as well as it did for me.

 

[Curtton]

good work , i will try it .

 

[Xman]

Edited for clarity.

 

[obiwanbonjovi]

If doing this be very careful. Removal of too much material can make rifle unsafe. Remember this is the sear surface you are messing with. make sure you leave enough material, while the steel is very hard it is not as hard as many other sears and requires more surface area to not shear. This will definitely improve trigger by removing creep, it will also make the gremlin far less likely to appear. This essentially increases overtravel of trigger system, by reducing creep. A lack of overtravel is what causes the gremlin to manifest itself. With 0 overtravel the rifles will fail to #### everytime as the sear must be pushed down to at least the point of release when striker rides back over it, if the trigger is not pulled past point of release, the sear will recatch on disconnector. The amount of overtravel necessary for the gremlin to not manifest, is determined by the inertia of sear when it is forced downward by striker, and the spring tension slowing the inertia. The inherent problem will still remain, as the carrier does not force disconnect before striker crosses sear, but with this added overtravel the problem should never manifest.

 

[Xman]

Remember this is the sear surface you are messing with. make sure you leave enough material, while the steel is very hard it is not as hard as many other sears and requires more surface area to not shear.

Actually it's not the sear. It's the striker. The striker nose to be more specific, but I do agree with being very conservative in filing material off. 1/32 should be enough. If possible, file of the smallest amount necessary and try it out. If the gremlin is still there, file off a bit more.

If you have one of those little vices that clamps to the table, take your vice and file to the range and do it progressively. This way you will absolutely not remove any more material from the striker nose than needed.

 

[Xman]

The problem is caused by the striker re-connecting trigger, by forcing the sear down too far during its rearward travel. The fix: more overtravel . How you give it more overtravel depends on why its happening, rifles that have the gremlin recurring often usually need the overtravel stop filed,

I was thinking about this today and after taking the trigger and sear apart, I think that what you actually need to do is add material to the trigger lip that hooks the sear rather than file some off.

A little material should be added at the end that is closer to the chamber. That way, when the sear is pushed down by the striker nose, it will not get hooked as soon. The sear reconnects to the trigger as soon as the sear heel passes beyond the little connector lip and gets hooked on its forward edge as the trigger spring pushes the connector upwards as soon as there is nothing in the way.

If that edge was further to the front, it would take the sear heel a little more traveling to get hooked on it, which means it would have to be pushed a little deeper. That's not likely to happen so the failure won't occur.

When the trigger is released after each shot, the top part of the trigger group move towards the back of the rifle and eventually the edge of the lip hooks the heel of the sear.

So, in conclusion, a different way to fix the gremlin would be to add a little material to the front of the connector lip.

I wonder if solder would be strong enough...

 

[Mayer]

Very interesting. Is it still problem free since the last 200 round trial?

 

[Xman]

Very interesting. Is it still problem free since the last 200 round trial?

I am going to the range tonight and will put at least 100 more rounds through the rifle with the filed sear. I'll try to think of ways to abuse it and push its limits.

I'll report back later.

 

[G37]

I plan on doing the mod that the US VZ-58 bolt carriers have; it seems like the best and easiest (if you know someone who can weld) method.

I haven't experienced the gremlin, but want to be sure I never do

 

[Xman]

I plan on doing the mod that the US VZ-58 bolt carriers have; it seems like the best and easiest (if you know someone who can weld) method.

I haven't experienced the gremlin, but want to be sure I never do

Yes, that would be ideal if you can weld or can get someone to weld it for you. Make sure you don't make it to long as the magazine must squeeze right by it.

 

[obiwanbonjovi]

I was thinking about this today and after taking the trigger and sear apart, I think that what you actually need to do is add material to the trigger lip that hooks the sear rather than file some off.

A little material should be added at the end that is closer to the chamber. That way, when the sear is pushed down by the striker nose, it will not get hooked as soon. The sear reconnects to the trigger as soon as the sear heel passes beyond the little connector lip and gets hooked on its forward edge as the trigger spring pushes the connector upwards as soon as there is nothing in the way.

If that edge was further to the front, it would take the sear heel a little more traveling to get hooked on it, which means it would have to be pushed a little deeper. That's not likely to happen so the failure won't occur.

When the trigger is released after each shot, the top part of the trigger group move towards the back of the rifle and eventually the edge of the lip hooks the heel of the sear.

So, in conclusion, a different way to fix the gremlin would be to add a little material to the front of the connector lip.

I wonder if solder would be strong enough...

the overtravel stop I was referring to is the little tab on the back of trigger that hits the receiver and prevents trigger from being pulled farther.

Solder is unquestionably not hard enough to lengthen tab on disconnector.

all of these methods you are describing effectively lengthen overtravel making gremlin less likely, however depending on how you fondle your trigger it may still occur. Just because there is more overtravel does not necessarily mean the overtravel will be used fully everytime the trigger is depressed.

 

[suprathepeg]

Yes Obi is right.

 

[Xman]

So, I got back from the range. I put 100 more rounds through the gun and the gremlin has not made a single appearance.

Again I fired the rifle is as many ways as I could think of; I even laid prone in the grass and took a run at a target and emptied a magazine on the run.

Another test I did was to bang the pistol grip on the table ( I took the magazine out on this one to avoid any accidents and did the test with just the one round in the chamber). The gun was cocked, a round chamber and the safety was off. I wanted to see if the striker could be bumped off the sear by shock. Didn't happen.

I also slapped the receiver on both sides and the top and bumped the stock pretty good with the heel of my hand to see if I can set if off that way.

I should mention that I was always pointing in a safe direction and was completely alone at an outdoors range when doing this.

The end result is more than satisfactory to me. When I got home, I took the gun apart and inspected the sear and the striker. No signs of distress or breaks.

If you can get the carrier with the welded tab, that would be preferable; if that's not an option, you will find that this is just as good, at least until we can get those tabbed carriers over here.

 

[Xman]

Has anyone tried the filed striker nose yet? I'd love to hear how it worked for you.

 

[Xman]

Put another 100 rounds through it today. It's getting a little cold on the prairies and I wanted to see if it would make a difference.

No gremlin; no problem of any sort...

 

[Stevo]

How many rounds through the gun before the gremlin first showed up?

 

[Xman]

How many rounds through the gun before the gremlin first showed up?

For me it showed up at around 20 rounds and then kept consistently reappear every 15-20 rounds, again.

I haven't had one since I filed the striker and I'm now at about 400 rounds.

 

[Curtton]

For me it showed up at around 20 rounds and then kept consistently reappear every 15-20 rounds, again.

I haven't had one since I filed the striker and I'm now at about 400 rounds.

and the simply remedy didnt work? like spring change.

 

[Stevo]

For me it showed up at around 20 rounds and then kept consistently reappear every 15-20 rounds, again.

I haven't had one since I filed the striker and I'm now at about 400 rounds.

Which one do you have? The 58S or the 858?

I've got about 700 rounds through my 858 with no sign of this problem.

 

[Xman]

and the simply remedy didnt work? like spring change.

I got "the kit" from Wolverine and it didn't make a difference. The gremlin showed up just as before.