P-01 w/ CGW Pro Pkg - Hammer stopped staying in fully cocked condition

[GregBFL]

I have a new CZ P-01 that I've polished the internals and installed a CGW Pro Package. Everything was functioning perfectly. DA trigger pull weight is 6 lbs 8 oz and SA is right at 3 lbs even. I sent my slide out to have it milled for an HS507K and when it returned I put it back on the frame to verify functionality. I always use an O-Ring in addition to a Snap Cap whenever I dry fire to prevent damage to the Firing Pin Roll Pin. DA works just fine but when I keep the Trigger pulled and rack the Slide, the Hammer follows the Slide back. The Hammer doesn't stay cocked and t's the same way when I try to manually cock it for SA.

Here's the strange part. I kept trying different things to see if I could get it to stay cocked but nothing worked. I finally tried holding the trigger back with one hand and pushing the Decocking Lever down with the other. All of the sudden the Hammer started working correctly again. It stayed cocked when racking the Slide and when I manually cock it for SA. I thought things were good even though I had no idea what caused the issue. The following day I started dry practicing and the problem came back.

I removed the Slide so I could see how the Sear and Hammer interacted when the Hammer wasn't staying cocked. It looks to me like the Sear isn't raising up enough to catch the Hammer and keep it cocked. I put a little pressure on the Sear with my finger to raise it up and it catches the Hammer.... But not enough to hold it back at the fully cocked condition. I then tried holding the Hammer back then activating the Decocker Lever and just like the day before, things go back to normal for a little while. It seems as though the Spring(s) or whatever pushes the Sear up far enough to engage the Hammer isn't pushing far enough at times. Why the Decocking Lever seems to fix things for a while is a mystery as well. If anyone can help me find the cause and/or resolution I would greatly appreciate it. Thanks

[GregBFL]

Wow, 80 views and no replies... Should I have posted this in the Gunsmithing subforum? I have studied the animated photos in the Gunsmithing/CZ Action Timing post (https://czfirearms.us/index.php?topic=73586.0) to see what makes the Sear move Up and Down. From what I can see the Sear Spring puts pressure on the Sear to keep it in the Down position and pressing the Trigger moves the Sear Up to allow the Hammer to fall.

At this point in time the Sear and Hammer are functioning as they should. The Hammer is locking back the way it should when the Slide is racked and when I manually cock it for SA fire. Unfortunately, I will not feel comfortable until I figure out what caused the Hammer to not stay fully cocked in the two instances. I have taken several photos of may P-01 with the Slide off so that you can see the orientation of the parts. You can also see the contact between the Sear and the Hammer. I also took two photos of the underside of the Slide after the Optic Cut. If you can offer any insight as to why the Hammer and Sear are not engaging on a random basis I would greatly appreciate your input. Thanks

Sear / Hammer Photos
https://imgur.com/a/Yo9jWAR

Slide Photos
https://imgur.com/a/OlIbEN8

[SI VIS PACEM PARRABELLUM]

Well the obvious thing is if DA works as normal but SA won't hold then the sear is not being allowed to drop into the proper position. I'd start by removing the decocking lever and looking it over for any burrs or deformity. Also look closely at the decocker spring and make sure it has not become damaged in any way.
If all looks well I'd lube it up good since it looks pretty dry and CZ's like oil then go run some rounds through it and see if it loosens up.
Something else I will tell you is that even though you installed the kit yourself CGW is very helpful with diagnosing any issues that may arise so it wouldn't hurt to give them a shout and run this by them as well.

[tdogg]

When you say everything worked perfectly, how many rounds did you fire to confirm this prior to sending in the slide?  Post slide mill is when the issues cropped up?  I don't know how that is possible.  I assume they didn't touch anything on the slide rails, they just milled the top for the dot?

DA works just fine but when I keep the Trigger pulled and rack the Slide, the Hammer follows the Slide back. The Hammer doesn't stay cocked and t's the same way when I try to manually cock it for SA.

Is the sear spring still intact and applying pressure on the sear?  If the hammer will not cock when manually actuated with your thumb, then something is holding the sear up or the spring has failed.

Does the hammer fall all the way down when it follows the slide forward or does it stop at the half cock notch?

I assume you installed the trigger with the Pro package?  Did you set the pre and over travel set screws?  You might want to remove/ back them off for troubleshooting.  These both can cause reset/firing issues.

I'm not sure what happens when you actuate the decocker lever and pull the trigger at the same time?  Both of these things are not associated with keeping the hammer cocked.  I wouldn't actuate both at the same time.  Is there tension on the decocker lever?  When actuated do you feel back tension on the lever as the hammer drops to the half cock notch?

I'd second calling CGW, they have seen it all and will probably be able to point you in the right direction in minutes.  My money is on the sear spring.

Cheers,
Toby

[GregBFL]

I really appreciate your responses, thank you! I will update you on the saga but first let me say I emailed CGW late last night and David responded to my email first thing this morning. Anyhow, yesterday when the issue started happening again I backed out both set screws to make sure they were not causing the problem and it didn't make any difference. I then thought there might be something wrong with the Safety Plunger on the slides so I pushed against the Firing Pin and the Safety Plunger limited the Firing Pin movement. I pushed down on the Safety Plunger and the Firing Pin moved further in exactly the way it should.

I spent quite a bit of time taking photos yesterday and sent links to the photos to David to look at. David's first concern was the depth of the Optic Cut in the Slide. David said they only make their Optic Cut a maximum of 1/8 (0.125) inch deep in the Slide and on a slope. The Wager Optic Cut in my slide was milled deeper than 1/8 inch but the Safety Plunger was working perfectly. That and the fact that I was still having the problem occur with the Slide OFF told me that it wasn't related to the Optic Cut.

David looked at all the photos and said he couldn't see anything out of place / wrong that would be causing the Hammer to not lock back. One thing that caught my eye while I was taking photos was how little the engagement was between the Sear and Hammer hook. Another thing I realized was when looking from the rear, only the Right Side of the Hammer Hook engages the Sear. The Hammer Hook on the Left Side doesn't touch the Sear when the Hammer is fully cocked. I mentioned this to David and said that it looked to me like the Right Hammer Hook was only engaging the Sear by 0.015 inch or so and he told me that by design it only supposed to have 0.018 inch engagement and that's about what my photo was showing.

David and I spent quite a bit of time on the phone going over my situation and when we couldn't find anything obvious causing the problem he said the next thing to do was disassemble the Sear Cage and see if there was something going on we couldn't see in the photos. I'm not sure what made me think of it but the day I received the Slide back from Wager I put a Snap Cap in the chamber and an O-Ring over the firing pin. As I was dry firing DA the O-Ring somehow got twisted and pinched between the Sear and Hammer. I'm now thinking that a small piece of the O-Ring might have came off and wedged itself in such a way it was keeping the Sear from going all the way down.

Last night I thoroughly clean everything before I started taking photos. I'm wondering if whatever was causing the problem was removed by the cleaning. I say this because I have DA dry fired 150+ times while periodically racking the Slide to verify the Hammer was locking back for SA firing. I also manually pulled back the Hammer 100+ times to ensure lock up followed by SA firing. The last time I had an issue with the Hammer locking back was yesterday. Since then all last night and all the testing today it has worked beautifully.

At this point I think I'm going to take it to the range and see how it does. I would have done it today but I live in FL and the better part of the day I've spent getting everything ready for the Hurricane. I will say that all the dry firing has helped to smooth out my trigger even further. I checked the DA trigger pull weight this afternoon and it's now 6 lbs 4 oz. From the Decocked state it's 6 lbs even. SA is 2 lbs lbs 12 oz which is a little lighter than I care for. David is sending me a couple Springs to increase the SA pull weight. I must say David and everyone I've ever talked to at CGW have gone out of their way to be helpful. Even though they didn't perform the install David spent a lot of his time going over everything with me via email and phone calls. That kind of service after the sale is pretty rare these days. I will say all my future CZ's will definitely have CGW parts in them. Once again, thank you for responding.

[tdogg]

Congrats on getting it sorted!  I'm guessing your root cause is correct, it was what I was thinking when responding originally.

Glad cgw was able to take the time to go through it with you.  This is a pretty common experience at cgw and it amazes me that even though David has built this business to be world renown he still dedicates this level of personal  customer service.  It's pretty rare in the world of online commerce.

Hope your range time confirms this is sorted!

Cheers,
Toby

Sent from my motorola edge (2022) using Tapatalk

[M1A4ME]

Have you noticed if the sear is engaging both the hammer hooks now that it seems to be working?  For future reference and curious readers.

My first striker fired M&P 9MM had issues with a dead trigger not long after I bought it.  I eventually took it all apart and found a tiny piece of plastic i the hole where the sear spring and plunger are located.  Got the piece out, took a picture and put a new sear spring in it and the problem was solved.  Two changes.  Can't say the plastic was the issue, can't say it didn't contribute to it.

This was down in the sear spring hole, so it was pretty small.  Sometimes it doesn't take much.

[tdogg]

Have you noticed if the sear is engaging both the hammer hooks now that it seems to be working?  For future reference and curious readers.

The P01 is a decocker variant and those hammers do not have two hammer hooks.  The decocker mechanism in the sear cage uses that side of the hammer to lift the sear and decock the hammer.  You can see how the left side is machined differently than the right on CGW's pictures here:  https://cajungunworks.com/product/80002-decocker-hammer/.

Cheers,
Toby

[M1A4ME]

I don't have any decockers (CZ) and I have never seen anything like that.  Wow.  I guess it works though.