Author Topic: How to adjust the Witness FPB timing  (Read 111 times)

Scarlett Pistol

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How to adjust the Witness FPB timing
« on: October 11, 2017, 12:03:21 PM »
So when I got my Witness Hunter (in 10mm, obviously) I dove in to figure out the action. It's slightly different than the CZ 75's I have. As I was checking things out I noticed that the FPB cleared the firing pin at the exact moment the hammer hooks broke away from the sear. Even though I had no FTF's in my first range trip I wanted to have a little sooner FPB clearance.

How to check this? I get a pen, pencil, or something to press on the back of the firing pin. I cock the hammer back and then hold it with my thumb in the exact spot it rests at cock. Then I put some pressure on the firing pin so it goes forward and contact the FPB. Then slowly pull the trigger and re-apply the pressure off and on to the firing pin. I hold the hammer so it doesn't fall forward when the hooks break away from the sear and crash down on my pen or fingers. When the firing pin block drops down enough it allows the firing pin to go forward. This will be very noticeable in how far forward the firing pin goes when pushed forward.

Back to adjusting the timing. So here's some pictures of the FPB and Firing Pin faces that engage.



So to adjust the timing the FPB face needs to drop down and out of the way of the Firing Pin sooner. There are two faces that you can remove material from. The first one seems to be the face that the extended FPB's require. I think I saw them at Patriot Defense and they were oversized...?  The second face is the one I removed material from.




I slowly removed material and would put things back together often. If you remove too much material the FPB will rest in a position where it never engages the Firing Pin. i.e. It is rendered useless. I removed enough that the FPB moves out of the way of the FP about half way through the trigger pull, rather at the end when the hammer hooks break away from the sear.

I would imagine this is the process I would use if I put in one of the Extreme Hammers with shorter hooks. Since I haven't gotten one yet I don't know exactly how they have the timing set, so I can't speak to how much, or if any adjustments are actually needed.

If anyone wants a little video clip explaining any of this just let me know. I also polished all the contact points on the FPB. The Witness Hunter comes very well tuned and polished so I didn't have to do much overall work to the pistol, but I can do walk throughs on polishing if anyone needs it. I have videos for manual safety CZ's, start to finish (disassembly, polishing, upgrades, mods, etc.) that I did for my comrades on the CZ forum. Since the Witnesses are a little different I can try to do something in the future if there's an appetite for it here for 10mm Witnesses.

PS- I am at a conference right now so I can't get to my pistols for more pics or videos till the end of the week.

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Scarlett Pistol

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Re: How to adjust the Witness FPB timing
« Reply #1 on: October 11, 2017, 12:06:36 PM »
Cajun Gun Works makes a Short Reset System for the CZ 75's. I think this could be accomplished with that extended firing pin block. When I am home I will get into my Witness and figure out more about the action and if this is the case. I'm sure some of you have figured this out already, so feel free to chime in. I'm not a pro gunsmith, Im just intermediate enough to help newbs to these CZ style systems.

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