Author Topic: Another Slide Lock Back Question  (Read 4120 times)

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n-10-MikeyMike-czechpistols82792

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Another Slide Lock Back Question
« on: March 23, 2003, 10:53:47 PM »
I have a CZ75 Compact PCR which is about 2 years old. I have put more than 10,000 rounds through it without a single problem. Recently, the slide has begun to lock back while there is still ammunition in the magazine. This problem occurs with all 3 of the magazines I have for the gun.
 
I have inspected the gun and the magazines and the only conclusion I can come to is that it's either the slide release/take down lever and/or the spring that holds it down. It seems to be moving upward while the slide cycles locking back the slide. I'm certain that it's not my thumb as I can't reach the slide release while holding the gun in shooting position. Has anyone else experienced this problem with their PCR's?

Offline ut83

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Another Slide Lock Back Question
« Reply #1 on: March 24, 2003, 06:04:52 AM »
Ill get all kinds of 'nah...thats not it....but it is!" :D
You need a new recoil spring.....Get a wolf 18-20# unit...
Myne does it every 1000-1500 rnds without fail and I always have a new recoil spring with me...after 1000 rnds anyway.
The slide speed slows enough that it will catch what its not supposed to.....
But with loaded mags....how does this work?....I cant explain it with any understanding...(its 5.00 AM...Im waiting for my Coffee :x :x   )
But it will work......
Shoot well :smokin

n-10-MikeyMike-czechpistols82792

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Another Slide Lock Back Question
« Reply #2 on: March 24, 2003, 06:28:01 PM »
I sent a mesage to Mike @ CZ before posting my message last night. He responded saying it's either a weak or bent slide stop spring. He's mailing me one today.

Last night I took a thin screwdriver and applied pressure to the spring right over where it spans the hole where the slide stop fits the receiver. Another thing I noticed was that the little groove in the slide stop itself was rounded on one side. I took a thin file and sharpened the groove. Perhaps this was the cause. In any event, it seems to be fixed.  I took the gun to the range today and put 100 rounds through it without problem.

BTW, I just put a new Wolff 18# recoil spring in the gun last week when the problem first started. In my case, it didn't seem to help.

Offline ut83

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Another Slide Lock Back Question
« Reply #3 on: March 25, 2003, 07:54:22 AM »
Maybe I need to look at my slide stop???????????
Thanks...Shoot well :smokin

Offline CZNE

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Another Slide Lock Back Question
« Reply #4 on: March 26, 2003, 10:55:54 AM »
I'm going to have to look at that slide stop groove too.  

I worked on my last evening.  I took the slide off, put the slide stop back in and then slowly inserted a mag into the well to see how close the bullets came to the slide stop as they moved up.  The clearance seems to be really tight.  Now, I've already removed a little metal from the slide stop and last night I removed a little more.  As you can imagine this is also affected by the type of bullet you are using.

The difference I see is that your gun has a lot more rounds through it than mine.  I can't believe your stop would suddenly start catching on bullets so it has to be something else.  Maybe I need to look at the spring also.

Good post guys, this little problem seems to be common and is a real PITA if we keep at it I think we can cure the problem.

Walt-Sherrill

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Another Slide Lock Back Question
« Reply #5 on: March 26, 2003, 03:47:01 PM »
I've never heard of a recoil spring causing premature lockup, but I suppose its possible -- if the spring is so weak that the slide is really slamming back when it recoils, that could BOUNCE the slide stop up.  

A weak or mispositioned slide lock spring might be a problem, too.

(Another person here felt he had a similar premature lockup problem due to TOO HEAVY a recoil spring.  That's different and not too likely, in my opinion.)

But UT83 offers good advice, regardless.  That's way too many rounds for one recoil spring.  (Keep it to 3,000 - 5,000 rounds the next time, please!)

thestretcharmstrong

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Another Slide Lock Back Question
« Reply #6 on: March 27, 2003, 09:44:36 AM »
If you have put 10,000 rnds thru the gun reliably, I think it may be foolish to start shaving metal.  I would definately start by bending the slide stop spring as described.  Getting a new recoil spring and mag springs from Wolff would be a good idea too, if they are all original.

I had a similar problem w/my 85Combat and I took some metal off the slide stop and replaced my mag springs and recoil spring.  This helped alot but I would still have a premature slide lock-up about every 300-400 rounds.  Better...but not fixed.  Then, I bent the slide stop spring as described and all seems to be good.  I think if I just bent the slide stop spring to begin with, my problem may have been solved alot sooner.

Walt-Sherrill

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Another Slide Lock Back Question
« Reply #7 on: March 27, 2003, 10:22:49 AM »
It might be helpful if you describe just what part and HOW you bent the spring.

(Think of all the metal shavings that won't be born...)

thestretcharmstrong

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Another Slide Lock Back Question
« Reply #8 on: March 27, 2003, 10:54:45 AM »
I did this about 2 months ago so it's not super fresh in my memory.  The spring is resting inside the right side of the frame.  For starters, I removed the spring.  Do a fieldstrip and push in the slide stop spring pin.  Then remove the pin w/needle nose pliers from the frame.  The spring should lift right out.  With 2 pairs of pliers, bend the long straight section of the spring slightly down at the knee to give more pressure against the slide stop.  Just do the reverse to reinstall it (the pin can be replaced from the outside of the frame going in.)  You will need to apply downward pressure on the slidestop spring in order to get the pin in.  Replacing the spring wasn't by any stretch a walk in the park.  Makes you feel like you need 2 more hands.

Walt-Sherrill

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Another Slide Lock Back Question
« Reply #9 on: March 27, 2003, 12:09:06 PM »
Seems like anything you do to INCREASE the tension of the spring would be inclined to make it -- if it were already doing so -- keep the slide open.  (It holds it open becuase of a strong spring; you have to work against the spring to release the slide.)  Hmmm....

thestretcharmstrong

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Another Slide Lock Back Question
« Reply #10 on: March 27, 2003, 12:30:18 PM »
The spring tension on the slide stop increases the tension it takes to release the slide (if that makes sense.)  In other words, it makes the release lever want to "stay up" more making it more difficult to lock the slide open prematurely or accidently by a light touch of the slide release lever.

Walt-Sherrill

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Another Slide Lock Back Question
« Reply #11 on: March 27, 2003, 02:00:49 PM »
I guess I'm just being dense (again) this afternoon... But, it seems to me that having the slide stop stay UP would make it more likely to catch the slide and stop it, not less likely!

When you RELEASE the slide, you press down on the slide stop.  

When the mag follower comes up the mag tube, the spring in the mag is pressing upwards on the follower so that the front of the follower presses on the underside of the slide stop, and pushes it UP, catching the slide and locking it open.

What am I misunderstanding?

For it to work properly, it seems to me, the spring tension has to be such that it keeps it in position JUST BELOW the height needed to lock back the slide, and not be so heavy that the follower, pushing up, can't make it move up and lock the slide the next time it passes.

(I've missed so many obvious things these past few weeks, I won't be surprised to have missed another. I find this analysis, like UT83's suggestion that a weak recoil spring is a possible cause of premature slide lock, beyond my understanding.  

Please note: that does NOT mean either of you are [wrong], but only that I don't understand...)

thestretcharmstrong

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Another Slide Lock Back Question
« Reply #12 on: March 27, 2003, 03:07:19 PM »
Walt,

It is more than possible that I am incorrect in the cause and effect of this.  I basically followed the instructions (as I posted) that were told to me by Mike at CZ.  The only thing that I know for an almost certainty is that an improvement was made.  I'll know for sure with more rounds fired.

Offline CZNE

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Another Slide Lock Back Question
« Reply #13 on: March 31, 2003, 09:44:51 AM »
I guess I belong to the school of, "just tell me how to fix it, I'll leave the why to someone else."  

I am going to take a look at my slide stop spring, I have a new recoil spring in, and most of my mag springs are new, so maybe it is the slide stop spring.

chuckdua

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Another Slide Lock Back Question
« Reply #14 on: March 31, 2003, 07:03:08 PM »
I have less than 700 rounds on my PCR purchased in 12/02. This slide lock back with a round still in the magazine has occurred 3x. Today was the third and as I paid attention this time it happened with a 13 round compact mag. I have a couple of 15 round mags for the B as well as the two 10 round mags that came with my PCR.

Is the recoil spring replacement a warranty item?