Upgrade hammer and Sear, pre-b cz 75

[boibosan]

I have a CZ 75 pre-b with spur hammer and safety.

Im looking into upgrading the gun somewhat for competition shooting.

I was looking into change the hammer to shadow2 hammer and then I read you need to change the sear aswell.
It has to be "fitted" for the safety, but thats minor.

Is this possible?

Another question is, the gun came with a straight SAO trigger but they sent the original DA trigger aswell but it was broken.

my question here is about the mechanism - I cant se how the trigger can cock the hammer as you dont replace any other parts in the trigger.
Or is it just that the DA trigger goes forward more (there is a cutout in it) then the SAO trigger so the trigger bar goes into another possition, that allows the coking of hammer, do I understand this correctly?

[tdogg]

If they converted it to single action only, then they should have removed the disconnector.  You will need a new disconnector (Shadow model should work) is what is needed to convert it back to DA/SA. 

Also, make sure the notch is wide enough for a shadow hammer to fit on the rear of the slide (where the firing pin is located).  The Shadow hammers I think are wider than other hammers and may not fit in a pre-B slide?  I don't own a pre-B.

If you want to run in competition, you should convert it back to DA/SA to be able to run in production.  Otherwise you will be running in Limited which will be competing with more race oriented guns.

Cheers,
Toby

[M1A4ME]

You can buy an adjustable sear from Cajun Gun Works that will take care of the "fitting" part of your question.  I've used a couple of them, easy to do, works great.  Can't remember, right now, if you need a spacer when using the CGW adjustable sear in a gun without the firing pin block.  Been awhile since I've worked on a CZ75 type.  Someone here will let you know.  Lots of knowledge here.

The hammer on the Pre B model is wider at the top where it fits into the slide to strike the firing pin.  A newer hammer should work, but it may look funny.

Are you wanting to run it single action only (SAO) or double action/single action (DA/SA?  If SAO the internal work may have already been done.  You need to remove the disconnector from the hammer. 

[boibosan]

You can buy an adjustable sear from Cajun Gun Works that will take care of the "fitting" part of your question.  I've used a couple of them, easy to do, works great.  Can't remember, right now, if you need a spacer when using the CGW adjustable sear in a gun without the firing pin block.  Been awhile since I've worked on a CZ75 type.  Someone here will let you know.  Lots of knowledge here.

The hammer on the Pre B model is wider at the top where it fits into the slide to strike the firing pin.  A newer hammer should work, but it may look funny.

Are you wanting to run it single action only (SAO) or double action/single action (DA/SA?  If SAO the internal work may have already been done.  You need to remove the disconnector from the hammer.

Right now it has the straight SAO trigger but the disconnector is still there, how does that effect the SAO trigger? Im waiting for a SA/DA trigger that i will install next week. The previous owner did use it for PPC SSA. But ods are I will fail a weapon check in the future. Im not doing IPSC right now, but perhaps later.

Didnt know the hammers had diffrent widhts, so I will probably not change that then.

The pistol did take both tangfolio and SP-01 18rnd magazines, so thats nice, its proofed 1990.

also have a CZ 85 combat slide for it that has LPA sights.

Overall, a really nice gun that I got (with 85 slide) for 1/4th the price of a new SP-01 or shadow. Barrels look fine and doubt there has been more then a couple thousand rounds fired.

[M1A4ME]

All I can tell you is that the disconnector isn't needed for SAO set ups.

I haven't heard that it actually causes any issues.  It might add a little extra friction moving around in the frame but I can't even say that for sure.

[Wobbly]

I have a CZ 75 pre-b with spur hammer and safety.

Welcome from Georgia.

Please take a few moments to familiarize yourself with all the sticky posts in the 'New Members' section. Together with the Help Topics in the 'Important Information' or 'FAQ' sub-section, these include 'how tos' such as 'how to' post pictures on the forum.

[boibosan]

If they converted it to single action only, then they should have removed the disconnector.  You will need a new disconnector (Shadow model should work) is what is needed to convert it back to DA/SA. 

Also, make sure the notch is wide enough for a shadow hammer to fit on the rear of the slide (where the firing pin is located).  The Shadow hammers I think are wider than other hammers and may not fit in a pre-B slide?  I don't own a pre-B.

If you want to run in competition, you should convert it back to DA/SA to be able to run in production.  Otherwise you will be running in Limited which will be competing with more race oriented guns.

Cheers,
Toby

Have been working on changing the trigger back to DA/SA from DAO and it took alot of work.

I notice the spurr hammer has a "half knock" notch but the gun refuses to stay on it - guess it either worn down or filed down by the previous owner. When kocking the hammer manualy I feel the notch.

Anyway back to the hammer - the spurr hammer is tinner up top then at the base. Looking at images on the shadow 2 hammer it looks similar but a bit wider, but still not wide as the base (that connects to the hammer spring), and looking in both my slides the slide is almost twice as wide as the hammer so I dont expect the hammer to touch anything.

But its mainly estetic, so I will probably let it be.

[boibosan]

You can buy an adjustable sear from Cajun Gun Works that will take care of the "fitting" part of your question.  I've used a couple of them, easy to do, works great.  Can't remember, right now, if you need a spacer when using the CGW adjustable sear in a gun without the firing pin block.  Been awhile since I've worked on a CZ75 type.  Someone here will let you know.  Lots of knowledge here.

The hammer on the Pre B model is wider at the top where it fits into the slide to strike the firing pin.  A newer hammer should work, but it may look funny.

Are you wanting to run it single action only (SAO) or double action/single action (DA/SA?  If SAO the internal work may have already been done.  You need to remove the disconnector from the hammer.

I thought I would update on this..

I measured the slide on the CZ 75 (pre-b) and CZ 85 Combat (no firing pin block), and the 75 frame has a gap of 0.355" (9,0 mm) and the 85 is 0.28" (7,15 mm). The spurr hammer is 0.234" (6,0 mm).

I have two slides due to diffrent sights (fixed vs adjustable), so they can be used in diffrent competitions.

Anyway, if i swap the hammer the 85 slide wont work, so i rather nog make that modification.

The more I look at the 75 i have the more confused I get. Its a long slide 75, no firing block, wide slide gap but the front sight is not removable (ie, its part of the frame), and the top of the slide is "round"

[tdogg]

You should go check out this section of the forum.  There is a good amount of info shared and displayed.

https://czfirearms.us/index.php?board=100.0

Cheers,
Toby

[M1A4ME]

If you plan to run the CZ85 slide more then swap out the hammer.  CZ used to make a later version (narrow enough for the CZ85 Combat slide) of the spur hammer.  I've bought a couple and put them on a CZ75 Compact and a CZ75 B .40 S&W.  Awesome hammers. 

CZ75B .40



It would still work (with the newer hammer) with the old Pre B slide, just have more gap in the cut for the firing pin slot.

[schutz85C]

Why not just install a Cajun Gun works Race Hammer and adjustable sear?
My 85 combat uses that.

Find a shadow 1 disconnector in case your pre B 75 frame does not have it..
Or phone Cajun Gunworks and ask for their appropriate disconnector

[schutz85C]

 https://czfirearms.us/index.php?topic=61135.0

Read this topic.
CGW also sells the CZ 85 trigger.
I have one to sell in case

[boibosan]

I bought a new hammer, the round one. But then the trigger became way to light (i need it to be around 1350grams SA to qualify for swedish national shooting disciplines)..

But after owning the gun a while and taken it apart more, im starting to think the previous owner changed the hammer and sear at some point - the spurr hammer is thinner then the 75 slide as to fit the 85 slide, and the sear must have been modified.

When i got the pistol the safety didnt work, so after filing the safety arm a bit on the sear it now works as intended. But the "half cock" possition on the hammer is either to shallow/modified or the sear is modified - im leaning to the latter.

So the previous owner must have replaced the hammer and sear at some point to be able to use the 85 slide with its adjustable sights.

Some day im going to get me a new proper CZ pistol but it shoots great for me. But the spurr hammer is not that good for IPSC as the hammer decocking is weird with the small grip surface.

Anyone know how diffrent the sears are for the cz75/sp01/shadow2? I have a hard time sourcing a new sear for 75 but the shadow1 sear is widely available, and the sear looks identical but i can be wrong.

[tdogg]

I only know of three different sears for CZ75 variants. 

Shadow/PreB/TS variant:  Wide with no room for firing pin block in cage
Safety CZ75:  Narrower to make room for firing pin block lever in cage
Decocker CZ75:  Narrow and no leg for safety block

Your preB should take the wide shadow variant sear that you said you can source easily.  I'm not sure how available CGW parts are where you live but they make a spacer that you can run to use the standard CZ75 sear as well.  The CGW sear is also adjustable to make fitting the safety very easy.

Cheers,
Toby