stumped, CZ-52 mechanical firing

[sonier]

OK, heres the deal. I have a CZ-52, I have had it fire on me 3 times when it was not suppose to. Im using handloads in a very mild/low power range. Starline brass sized once never fired. Im using sierra 85 grain fmj .308. I recently took the gun apart. The pistol also is stock from when it was bought from a dealer as surplus 10 years ago.

Ok whats going on is usually this.

I will load a magazine chamber a round fire 3 4 times.

Then i Decock the hammer like I do a revolver and just guide it down.

No problems.

When i get ready to fire another shot, I start to pull the hammer back,

about half way the gun fires.

This has happened 3 times and im 99% sure i didnt accidently pull the trigger. and even then how is it possible to pull the trigger when the hammer is only half cocked and the gun fires.

Also i have taken time to disect this pistol, there is a plunger that unlocks the firin pin when you pull the trigger, but there is no weigth on the firing pin because the hammer has to hit it, to make it fire. so logically my problem seems impossible to happen.

I am completely stumped. AND NO I WILL NOT TAKE IT TO A GUNSMITH Im going to be attending gunsmithing school for 3 years and plan on 4th year invitation only, Ive freefloated barrels, set trigger pull weight, cleared stuck shells. If anyone wants to give me some ideas thats nice but i want everyone to know absolutely no way will i take this gun to a gunsmith, I will tear it up and give it to a gun buy back program if i cant fix it myself.

 

[rcmodel]

I can think of no reason at all that would allow a CZ-52 to fire without the hammer hitting the firing pin to fire it.

The firing pin has no stored energy of it's own, and simply cannot fire a round without being broken or stuck foreword when the round is chambered.

Or by getting smacked by the hammer after it is loaded, in battery, and cocked.

It could conceivably receive enough energy to fire from a partially cocked hammer, were your thumb to slip off the hammer.
Especially with softer primers in your handloads then the normal hard military primers.

There have been many reports of the CZ-52 firing when the de-cocker was used to drop the hammer. But that also involved a defect in the de-cocker design, and allows the hammer to hit the firing pin.

rc

 

[sonier]

I had the decocker fire on me once, but thats what i thought, it seemed inpossible to fire because the

firing pin is just freefloating in there. Im wandering if i slipped the hammer half way and maybe

that was enough to hit, im using wolf primers i think there soft primers too.

 

[Roccobro]

The decocker has been known to cause firing on these guns. IIRC it has to do with Firing Pin wear.

Sonier- try to mimic the actions with an unloaded gun. Watch what happens. I'm thinking the hammer is releasing prematurely and your softer-than-surplus-primer hand loads don't mind it "going off half cocked."

Justin

 

[JohnKSa]

Is the firing pin safety functional?