Problem with my CZ40B


March 20, 2005, 04:52 PM
My CZ40B had a weak recoil spring. It has been replaced by a 20# recoil spring so now the shells eject about 6 feet away instead of 20 feet away. It also has a lighter hammer spring installed.

Yesterday I went shooting and I shot about 150 rounds of this Russian ammo I bought, it has steel jackets instead of brass. It's not Wolf ammo but it looks similar. It doesn't say a brand on it.

The problem I had was that 2 out of the 15 clips I shot didn't quite work properly... I got to the point where there was 2 bullets left in the clip, and the slide locked back as if the clip was empty. Releasing the slide, I could fire the last 2 bullets then it would lock back again like it is supposed to.

The gun was clean and well-oiled so I am not sure what would cause this. I didn't have any normal brass-shelled ammo to compare with. Do you think it was the ammo or something wrong with my gun?

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March 20, 2005, 04:56 PM
It sounds like the ammo. I would test it with some qaulity ammo before jumping too hard on the gun.

March 20, 2005, 05:25 PM
You might want to also replace the mag springs with Wolff. Not that this has anything to do with the problem, because a weak mag spring would cause the slide to NOT lock back.

Switch to better ammo and see if that cures the problem. The only guns I use steel case ammo in is AK, SKS and Makarov.

March 20, 2005, 05:37 PM
Slide lock back is a sign of a recoil spring getting weak.....generally, speaking that is. If its new then you have ammo/mag spring issues. Wolff makes great mag springs. I had the same problem with mine...............

Shoot well.

March 20, 2005, 06:06 PM
You know, looking back, I seem to remember this happening with some Fiocci ammo at a shooting range (brass shells). The slide locked back prematurely a couple times. I seem to remember looking into the breech hole of the slide and seeing that the next bullet in line was sticking forward farther than it should. I think I will try new magazine springs and see if the problem goes away.

March 20, 2005, 06:51 PM
Hellbore......if that is the case, then you need to tap your mags to seat your rounds. I do this habitually every time I load a weapon, it seems to prevent that from happening.

March 20, 2005, 07:24 PM
I had this problem with my Beretta 92fs. I couldn't seem to find anything wrong with the gun or the ammo. I couldn't find a pattern until I realized that it only happened when I was using a two hand hold. It seems I was hitting the slide stop with the thumb of my left hand. :o A change of grip and no problems.

You never know what the problem is so it is best to start with the easiest to fix.

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