CZ Kadet Mainspring

[czrami9]

I called CZ today to ask for advice, as my Kadet has been failing to fire on the first and second rounds in a mag if fired from single action mode. The technician advised me to put in a 20lb what mainspring from Wolff. "Ok, sure. Thanks" Then I hang up and think to myself, you moron, you don't know what a mainspring is or how to change it. I know about the spring around the guide rod (recoil spring?), and the spring around the firing pin (firing pin spring?). Where is the mainspring, and how do I change it out?


PS. Despite my apparent incompetence, simple directions on where this is and how to do it will be sufficient (I hope) to helping me get this fixed). Thanks!

 

[gb6491]

If you will scroll down to where the grips are being removed on this page, the following photos and text will show you where the mainspring is and how to remove it.

I bought my CZ75b used and it has a great trigger. With that in mind, I was having failures to fire with my Kadet kit. At first, as the hits on fired cases looked pretty much the same as the ones that failed to fire, I chalked it up to the Federal bulk pack ammo I was using. However, the problem persisted with CCI and Federal Champion. Everything on the pistol looked good; no burs, bends, dirt and good pin protrusion from the breech face). I thought about a heavier mainspring, but didn't want to mess up the trigger pull (never had a problem with the 9mm top end). So, I modified the firing pin to let a little more protrude (you have to be careful here as too much firing pin protrusion and it would hit the chamber face if dry fired), but the results were the same. I got to wondering if the chisel tip of the firing pin was the culprit. My first thought was that the surface area was not large enough, but now I wonder if the problem was that it wasn't finished squarely (or flat enough); so that a slight angle on the tip allowed most of the energy from the hit to be dissipated on the outer edge of the case. I took the tip down some making sure it was flat; this also increased the surface area. I then checked and compensated for the slight length reduction of the pin. Whatever the reason for the FTFs before, the pistol has been pretty much flawless with all ammo since this modification to the firing pin.
Modified firing pin hit on the right:


Regards,
Greg

 

[czrami9]

Thanks man! I will have to take a look at that tonight.

 

[czrami9]

I looked at mine tonight. I put some spent brass in the chamber and fired from single and double action mode. The single action mode barely left a small circle dent. Double action left a small circle, but nothing as pronounced as above. Any suggestions? I'm thinking the firing pin doesn't protrude enough. Where do I need to file to make it protrude more?

 

[gb6491]

The single action mode barely left a small circle dent. Double action left a small circle,

Does your firing pin have a circular or chisel shaped tip? I believe the chisel shaped tip was an upgrade/fix. If yours isn't you might give CZ a call about replacement.


In regards to your current firing pin;
First look at how much of the pin head is available for the hammer to strike.
This is what mine looks like:

Remove the firing pin and spring from the slide, then reinsert the pin sans spring. Push it as far forward as it will go and hold it there. Now check the face of the slide and see how far the pin protrudes from the hole. The photo shows how far it does on mine. The pin should never protrude farther than the semicircular step above it in the photo.

if you remove material from the shoulder indicated in red you will increase how far the pin protrudes from the breech face. Removing it from the opposite shoulder will increase how far it protrudes from the firing pin stop.


Regards,
Greg

 

[czrami9]

Thanks for your help. I have the rounded firing pin. I will call CZ and get them to send me the upgrade and see if it helps. Thanks my friend