Author Topic: SP01 Shadow Stopping at half cock  (Read 1221 times)

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Offline Tony P

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SP01 Shadow Stopping at half cock
« on: July 29, 2019, 08:27:29 PM »
So I broke out the CZ last month to shoot a little carry optics and thought I was getting light strikes on my reloads.  4 out of 10 stages at the match first round did not go off, pulled the trigger again went bang and kept shooting.  Thought it may have been the hammer spring primer combo (11lb, Winchester) although I shot that combo for years without issues.  Went to the basement today for a little dry fire and pulled the trigger a couple times in DA and noticed the hammer stop at half cock.  just pulled the trigger fast 20 more times or so and I get it to stop at 1/2 2 or three times.  I didn't do a lot of experimenting with it but if I gripped it tight and put pressure on the bottom of the left side safety from my normal grip it happened more often.

I've completely stripped it, not reassembled yet!!  I admit it was pretty dirty!!!   I didn't notice anything obviously wrong but I'm not a gunsmith so maybe I wouldn't.  Gun started out as a stock SP01 Shadow, think my list of parts are CZ Comp Hammer, Pre B disco and springs,, all this work was done 12k to 15k rounds ago with no issues.  I started shooting limited 2 years ago so not much use out of the shadow.  Got the slide milled last year and have taken it out once in a while, maybe 500 rounds in the last year.  Same can of reloads I've always been shooting.

Any insight would be appreciated, I'll get it put back together tomorrow and see if I can duplicate the problem.

Thanks

Offline aandabooks

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Re: SP01 Shadow Stopping at half cock
« Reply #1 on: July 29, 2019, 08:39:36 PM »
Not enough rounds to be a hammer and rear.  At least it shouldn't.  Reassemble clean and try again.

Offline Tok36

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Re: SP01 Shadow Stopping at half cock
« Reply #2 on: July 29, 2019, 08:49:42 PM »
I suggest checking the Trigger Bar Spring tension and positioning while you have it striped.
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Offline Tony P

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Re: SP01 Shadow Stopping at half cock
« Reply #3 on: July 29, 2019, 09:00:30 PM »
Trigger bar has not been removed so I'll mess with that also, one other thing I just remembered my trigger didn't reset a couple times on the first two stages then was a real mess on the third, went to safe area field stripped and I had a spent primer in the frame where the trigger connects to the trigger bar, no more reset issues after removing that but maybe I had some junk in there.  Thought I'd post while letting some parts soak.

Offline eastman

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Re: SP01 Shadow Stopping at half cock
« Reply #4 on: July 30, 2019, 10:23:52 PM »
I suggest checking the Trigger Bar Spring tension and positioning while you have it striped.

this is my thought as well
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Offline Tony P

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Re: SP01 Shadow Stopping at half cock
« Reply #5 on: July 31, 2019, 05:33:00 PM »
Stripped cleaned and reassembled, worse now, taking back apart tonight.   DA pull results in half cock most of the time

Offline Tok36

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Re: SP01 Shadow Stopping at half cock
« Reply #6 on: July 31, 2019, 07:28:57 PM »
   This still sounds like a Trigger Bar Spring tension issue to me. I am thinking the Trigger Bar is slipping off of the lower leg of the sear towards the end of the Double Action pull.

   I suggest increasing the TBS tension on the left side. This can be accomplished without full disassembly. Removing the grips and slide should give you access to the TBS. Swing the left side leg of the TBS out from under the Trigger Bar so that it rests against the inside of the Trigger Bar. Bend it up a bit so that it sits higher up the inside of the Trigger Bar. Then reposition it under the Trigger Bar into the groove. With the grips off reinstall the slide and test it to see if there is any change. If the malfunction still occurs add a bit more tension. For reference the TBS leg when moved out from under the Trigger Bar should sit around 1/8"- 1/4" above the lower edge of the Trigger Bar. I would also check the Right side TBS tension while you are in there.

   If this was occurring in Single Action i would be moving towards the Disconector/Trigger Bar clearance but i can not see how the Disco could be causing this in Double Action.

Here is a reference picture of the TBS and how it can be accessed with the grips removed. Note: In this picture the TBS is not in the groove in the underside of the Trigger Bar, it should be in the groove.

« Last Edit: July 31, 2019, 07:35:08 PM by Tok36 »
Will work for CZ pics! (including but not limited to all CZ clones)

Offline coolbox

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Re: SP01 Shadow Stopping at half cock
« Reply #7 on: August 01, 2019, 06:42:52 AM »


This might help maybe. It was a different problem, but maybe due to the same reason.

Complete thread here

https://czfirearms.us/index.php?topic=66124

Well, as it turns out, schmeky was correct,as was mtops. The trigger bar was actually giving uneven pressure, and lifting unevenly. Left side was lifting up first. I bent it down using nose pliars.  It is fixed now, and there is no false reset. Below is the step by step fix from schmeky,


1. Remove the slide
2. Cock the hammer in SA
3. Push down on the trigger bar and at the same pull the trigger all the way back
4. The hammer should now be fully cocked in SA and you should be holding the trigger all the way back
5. SLOWLY let the trigger go forward and watch the 2 humps in the trigger bar - one will jump up sooner than the other
6. The one that jumps up first has to much "up" tension on the trigger bar support spring (#34)
7. Bend the #34 down at little at a time until both sides of the trigger bar pop up at the same time

I was doing step 3 all wrong. It has to be done as mentioned above. With the hammer cocked, press the trigger bar down, then pull the trigger all the way back with the bar still pressed down. Then once the trigger is all the way back, release the bar. Then move to step 4.


Should this fix be a sticky?




In DA, while slowly squeezing trigger, if I just release the trigger (take pressure off, do not pull fully) back right before breaking point, it stays in SA mode, instead of the usual half cock mode. I can also hear a little click. I can repeat this and make it happen every time. I do not think I have encountered this before.

Well, while I did resolve the SA reset issue, I cannot resolve this DA problem one. Actually, I went back to OEM disco and FPB liftin lever. Now, today I had the chance to go back to custom stuff, from CGW, and I am facing the problem. And the problem reappears. This has been discussed on forum in one sense or the other, that the disco needs to be worked upon to solve the timing issue. But which part of disco for this problem? The problem, I repeat, is simply that the gun converts from DA to SA if I pull the trigger and stop a fraction before the point where the DA breaks. The SA hooks are engaged before the DA breaks.

I know CGW will get me sorted out, but I don't recall having heard this one before. So, waiting for comments, and a remedy!!

Well I figured it out. It is solved finally!!

I removed material from the face of disconnector that is pushed back by the trigger bow. By removing material, the DA cycle completes before it gets to go all the way back to engage SA hooks. I am yet to check at the range, but dry fire was alright. While I was at it, I did change safeties to SP01 Shadow style.
Life is too short to waste on a bad trigger pull

Offline Tony P

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Re: SP01 Shadow Stopping at half cock
« Reply #8 on: August 02, 2019, 05:28:01 AM »
I don't know for sure what fixed it, took it back apart and reassembled, I had a spare trigger bar spring so I swapped it out, nothing looked wrong but hey it seems to be working now, maybe I'll get to the range today to try it out!!!     Thanks everyone for the help

 

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