CZ 75B .40 slide release issue

[Ace_Breaker]

I took my CZ out for the first time today and put 200 rounds through it. For some reason the magazine release would engage after a few rounds. It did it on and off about every 10-15 rounds. It was not a loading issue, the rounds never even touch the barrel. It just completely locks the slide back as if the magazine were empty when it's not. Otherwise it shot perfectly and is the most accurate of all of my handguns. Any ideas???

[Ace_Breaker]

Oops, ok, I'm tired. It's not the mag release, it's the slide that's going back and locking. Hope it all makes sense now. I need to find a fix!

[Ace_Breaker]

Wow, I was hoping to get some help from all the pro's over here, but not one response. I had to get the information from a 1911 forum! Not even a response from CZ, just straight out ignored! For anyone who cares or is having a similar problem, apparently my rounds are hitting the slide release as they come up. I use a high grain bullet. The fix is to grind off a little of the metal so the round won't hit, but not so much the the magazine will still hit when the mag is empty.

[Walt Sherrill]

With a new gun, this might be a slide lock that's a little out of spec. I had that with a new CZ-85 Combat a few years back. My gunsmith removed a little material from the "nub" that engages the magazine follower and it never burped again.

In a gun that has been fine but is suddenly having the problem, it might be coming from weak mag springs. (When they're loose, they let the topmost round get pushed forward, under the slide, as the slide slams home...this can engage the slide stop as the next round is readied for chambering.)

This is more likely to be true if it happens only with one mag, and not others. New springs might fix the problem. (WWW.GUNSPRING.COM -- look for the EAA springs.)

The same thing can happen with overlong ammo (some handloads). Check the slide stop and see if you see some copper on the nub where the slide stop engages the follower of the mag.

Check the CZ-Forum for more specific responses to CZ questions. Here:

http://p201.ezboard.com/bczechpistols82792

[cbailey]

My new 9mm 75B was doing the same premature slide lock - last week I dremeled quite a bit off the offending nub. This excess protrusion also prevented magazines with cartridges still in them from dropping free (I had straightened the magazine brake so I was hoping they’d drop free).

It was hanging up with cartridges of various OAL’s, from my 147 grain handloads to 115 grain WWB and Federal American Eagle.

Haven’t got a chance to try it out yet since I shortened the nub. I am really hoping this solves the problem as otherwise this is a very neat pistol - best feeling double-stack nine I’ve held.

[Ace_Breaker]

Thanks guys. I'll think I'm going to shave a little metal off and see how it goes.

[briang2ad]

The 40 slide stop has MUCH LESS metal to engage the mag follower. The 9mm is thicker at this point, so...

If you have a 9mm slide stop, it will hit the 40 rounds (they are larger) coming up in to the chamber area, and that may bump the slide stop into engaging the slide. In addition to this, it can create feeding problematic. If you have a friend with a 9mm, or a local shop, you can check. If you have the wrong one (9mm), CZ USA will send you a new one for the 40 if your gun in under warranty (and maybe they will even if it isn't).

If you ever want a CZ Kadet 22 conversion kit, you WILL need the 9mm slide stop to work with the 22 kit.

[Ace_Breaker]

Mission accomplished! I shaved a slight amount off and repainted the slide stop. I can now see a little clearance between the nose of the rounds and the slide stop. It has plenty of metal to catch on an empty magazine so appears that it should work just fine. I'll test it out as soon as I can. I'd rather run dry than chance having the slide stop in the middle of a magazine. :eek:

[Ace_Breaker]

Update-I ground off a little of the slide lock where the noses of the rounds were hitting. I then went and shot 300 rounds this morning. No problems at all in the first 150 rounds. Then I had a sporatic 5 slide locks with the next 150. Much improvement over having the slide lock about every 10 rounds or so. I was slightly discouraged that I have to go through the process again and started doubting my fix. The good news is that when I took my weapon apart I looked where I had painted over the slide lock where I had ground the slide stop down. The paint was worn off, clearly showing rounds are hitting it. There is plenty of material left to grind off and I will still have plenty of metal so that the empty magazine will activate the slide stop.

[briang2ad]

It just may be it.

[Ace_Breaker]

Final update! I ground down the spots rubbing on the metal slide stop again. I put 350 rounds through the gun with the slide locking back once while ammo was still in the mag. I took the gun apart and could see where it had worn the paint off again. I did a little more grinding on the one spot. I'm happy with the 350 round performance. Not perfect, but after one last grinding I'm sure it will work just fine now. There were no other malfunctions or problems to report. The weapons shoots great and is super accurate. For a celebration I just ordered a P01 with my dealer!!!

[briang2ad]

put out another 40 with a 9mm slide stop. It happens.

[Ace_Breaker]

You may be right. I'm sure I fixed the problem, but it didn't leave a whole lot of metal left to catch the bottom of the magazine. I contacted CZ and they just sent me an extractor spring and slide stop on them! Great service after all!

[ZeSpectre]

I've had a few thoughts on this.

1) As mentioned, 9mm slide stop on a .40 S&W gun. I've never seen this but have heard of it before.

2) Do you shoot lefty? I've seen (and done it myself) where my right thumb pushes on the frame right at the end of the slide stop pin. Just the right (wrong) push and I've pushed the pin loose before causing the slide to lock.

3) Wrong finger position shooting right handed can sometimes cause you to nudge the slide stop up. In that case adjust your grip.

[Ace_Breaker]

Hello and thanks for the response.

2) Do you shoot lefty? I've seen (and done it myself) where my right thumb pushes on the frame right at the end of the slide stop pin. Just the right (wrong) push and I've pushed the pin loose before causing the slide to lock.

I shoot right handed.

3) Wrong finger position shooting right handed can sometimes cause you to nudge the slide stop up. In that case adjust your grip.

I had shown an armorer then went shooting with him. I didn't realize it, but he was looking at the same things you suggest. He said that my fingers were well below the slide stop. I've never engaged a slide stop on accident. My grip is a tactical grip that is used on most of my weapons and the positions sit low of the slide.

It's 100% a slide stop length issue. I went from malfuntion 1 in 10, then after grinding 1 in 50, then grinding more and 1 in 350. Every time I could see wear on the painted end of the stop where it hits the nose of the bullets. The CZ armorer suspected the spring and stop so sent me both parts. I'll probably shoot to check my latest grind. If it's hassle free in 300-400 rounds I'll assume it's fixed. Any problems and I'll change out the slide lock. Thanks!

[briang2ad]

Good. I was hoping you'd get with them - they're pretty good about parts replacement. If you look at a 9mm and 40 slide stop next to each other, you wonder how the 40 stop EVER catches enough follower to stop the slide - but they work. The 9mm one has so much metal, it leads to more than stop, issues in a 40 - it consistently bumps the rounds which can lead to your problem, plus FTFs, and FTE's. I forget how I figured this out, but I did on my gun, then heard about it from another guy on the CZ Forum site.

I was hoping you would just replace it, so when you get a Kadet (most want one), you'd have the RIGHT slide stop. The 40 SS will NOT lock the kadet kit after the last round. You would then need the 9mm stop.

[Ace_Breaker]

Thanks for the response.

Actually, the CZ armorer said that it is normal for rounds to lightly rub into the slide stop. There is probably a designed reason for that?

I don't know anyone that has a 9mm of hand. It seems that few know what a CZ in my area. At a large gun show recently I only saw 2 or 3 of them and they were priced around $500. Nobody knows what Tanfoglio or EAA is either. I've shown mine and shot with a few people. They've started to read up on CZ's and are thinking they might have to have one.

No Kadet kit for me right now. I'm using mine for defensive and carry. I've got probably 6 full cases of .40 Speer dot waiting to play!

[mthalo]

It just completely locks the slide back as if the magazine were empty when it's not. Otherwise it shot perfectly and is the most accurate of all of my handguns. Any ideas

I had the same issue with my CZ75BD 9mm. I contacted their gunsmith (which I see you've already done, I agree about the great service) and he immediately sent me a new slide stop spring. That solved the problem.

I've heard (but cannot verify) that some were produced with weak springs, so while I was at it, I replaced the standard 14lb recoil spring with a Wolff 16, and replaced the extractor spring.

After the upgrade, it hasn't failed in any way.

[Ace_Breaker]

Thanks Mthalo, that gives me confidence that I'll get it fixed one way or the other. I want it to be reliable or I won't be able to trust it as my primary gun. I've been carrying my Sig around until I know the CZ is cured.