CZ P09 ignition problems

[GJM]

@ralph, with all due respect to @timotab's hard work, I wouldn't consider his one home-modified and untested gun a robust solution to this issue. Personally, if I had to grind on parts of my CCW to make it reliable, I wouldn't carry it. Timotab's work does provide an excellent clue about the mechanics of how the hammer drops to half cock.



My testing suggests that I can press the trigger fully to the rear and the hammer will drop normally no matter what the timing. Only if I interfere with the trigger press by putting something (that reduces force) behind the trigger at just the right point will it drop to half cock instead of firing. This is a big difference to me, and suggests that in my hands, the conditions needed to cause this issue are very contrived.

On the other hand (pun intended) in your hands, this seems to happen much more easily. I think it's similar to people whose hands and grip cause the slide lock to be activated during shooting in some guns, and not at all like the p320 issue.

I do agree that CZ-USA or CZ-UB will be the most important to hear from.

I am hopeful CZ will identify, study and solve this, as I love the pistols.

[Francis]

May I interrupt for just a minute to say thank you to everyone who is making the time and effort to post their findings? The methodical analysis and civil discussion of this thread is not only valuable and educational but also a breath of fresh air. Many thanks.

Update: Not that other discussions aren't valuable or civil but I've been following this one closely.

[ralph]

@ralph, with all due respect to @timotab's hard work, I wouldn't consider his one home-modified and untested gun a robust solution to this issue. Personally, if I had to grind on parts of my CCW to make it reliable, I wouldn't carry it. Timotab's work does provide an excellent clue about the mechanics of how the hammer drops to half cock.



My testing suggests that I can press the trigger fully to the rear and the hammer will drop normally no matter what the timing. Only if I interfere with the trigger press by putting something (that reduces force) behind the trigger at just the right point will it drop to half cock instead of firing. This is a big difference to me, and suggests that in my hands, the conditions needed to cause this issue are very contrived.

On the other hand (pun intended) in your hands, this seems to happen much more easily. I think it's similar to people whose hands and grip cause the slide lock to be activated during shooting in some guns, and not at all like the p320 issue.

I do agree that CZ-USA or CZ-UB will be the most important to hear from.

It wasn't my intention to call timotab's modfication a hard solution. It is however, a very promising start. I agree that people like GJM who grip the gun like they do, the P09/07 series may present a problem, but for the rest of us, I don't think it is.. If CZUSA or CGW starts studying the issue,(if I had to guess, CGW will likely take the issue much more seriously) we might see a change to the trigger bar. Honestly, I don't think CZ is going to take it that seriously, simply because they've sold tens of thousands of them, with few issues, and this is a pretty isolated incident .. All anyone could do at this point, is bring it to their attention.. I need to put a few more rounds through mine, but at this point, I'm not seeing any reason not to use it as a carry gun..

[ralph]

How many instances of the 320 being dropped and firing, before we considered that a problem?

How many other quality pistols do we have, where without trigger tab interference, we can press the trigger fully to the rear, and based on the timing of that press, the gun doesn’t fire?



I am very interested in what they say, and as the manufacturer, I consider them the most important voice.

If I had to guess, we're going to have to more than the number of people who are having the issue now. 4 or so people having the problem compared to God knows how many who don't, is at best, an isolated incident..Now, if all of a sudden, you have several hundred who have the same issue, then yeah, you have a problem, but so far, we're not there..We just don't have the data. As far as your second question, I don't know. One thing about the 320, it's my understanding that SIG was aware of the problem, yet kept shipping pistols out.. If that was truely the case,(and I've no idea as I don't keep up with SIG,as I have little interest in them) then that was managment's fault..and they own it.. And they deserve to have their asses sued off if anyone gets hurt as a result. No pistol is perfect, all are a compromise of one sort or another. You know that better than I do. If a pistol has more flaws than you're willing to live with, then sell it and move on, that really, is about all you can do..

[ralph]

Double post

[timotab]

I wonder if adding a couple of roller sizes to CGW's catalog would be all it would take to have a plug and play way to eliminate any chance of this occurring. Maybe 0.210 and a 0.215. I'm tempted to buy a 0.230 roller and see if it makes it easier to induce a malfunction.

[Trukinjp13]

I wonder if adding a couple of roller sizes to CGW's catalog would be all it would take to have a plug and play way to eliminate any chance of this occurring. Maybe 0.210 and a 0.215. I'm tempted to buy a 0.230 roller and see if it makes it easier to induce a malfunction.

I measured mine and it is around .215-2.18. I am curious if this gets enough traction, will CGW or CZ USA step up with a off the shelf solution.

I am in the camp that if this is a design issue (which it is) then it needs to be rectified. Even if my gun is not doing it under normal circumstances for me. There is always a chance. Winter time with big ass gloves on. My buddy with giant hands has to use it etc. I am concerned as has been mentioned this has happened a lot of times. Problem is got chalked up as some random failure or ammo related. Vast majority of people have no fucking clue what is what if their gun does not go bang. Ignorance is indeed bliss

[GuanoLoco]

I wonder if adding a couple of roller sizes to CGW's catalog would be all it would take to have a plug and play way to eliminate any chance of this occurring. Maybe 0.210 and a 0.215. I'm tempted to buy a 0.230 roller and see if it makes it easier to induce a malfunction.

It’s pretty clear that CZ uses a variety of diameter rollers to time the system, presumably to compenate for tolerances / tolerance stacking. Without testing this would be my first guess/step - try a size larger and a size smaller smaller rollers.

[ralph]

I wonder if adding a couple of roller sizes to CGW's catalog would be all it would take to have a plug and play way to eliminate any chance of this occurring. Maybe 0.210 and a 0.215. I'm tempted to buy a 0.230 roller and see if it makes it easier to induce a malfunction.

I think what you might have to do is, to get a set of rollers made in say .002 increments, from say .224-.210 and either start at the low end and work your way up, or start at the large end and work your way down. Somewhere in there you'll find the sweet spot, (at least for that pistol), you could then narrow it down farther with a couple made in .001 increments, within the roller's size range..Making the rollers should be a simple project for someone with a mini lathe..

[GJM]

I think what you might have to do is, to get a set of rollers made in say .002 increments, from say .225-.210 and either start at tne low end and work your way up, or start at the large end and work your way down. Somewhere in there you'll find the sweet spot, (at least for that pistol), you could then narrow it down farther with a couple made in .001 increments.Making the rollers should be a simple project for someone with a mini lathe..

Either that, or the company that designed and manufactures the pistol could figure it out and save us all a lot of trouble.