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CZ LONG ARMS => CZ Scorpion EVO => Topic started by: SilverBullet76 on October 29, 2019, 11:54:33 AM

Title: Bolt not locking back on the last round
Post by: SilverBullet76 on October 29, 2019, 11:54:33 AM
Hi all.  Newbie here and to Scorpion Evo.  My bolt is not locking back at the last round and I was wondering if anyone can help and tell me what the culprit is.  I only use original factory magazines.  Upon inspection I noticed the corner of the bolt that engages the bolt catch/release is rounded off.  I was wondering if anyone can compare mine to yours.
(https://i.imgur.com/tWxFIKbl.jpg)
(https://i.imgur.com/E6REIADl.jpg)
(https://i.imgur.com/06wpnatl.jpg)
Title: Re: Bolt not locking back on the last round
Post by: Hemiscorpius lepturus on October 29, 2019, 08:02:40 PM
that is... bad.

there is no way the bolt will lock with that much rounding, the radius of that area should be under 0.1mm, yours looks like over 1mm

I also have no idea why the other side is rounded, since the bolt catch is only on the left
Title: Re: Bolt not locking back on the last round
Post by: SilverBullet76 on October 29, 2019, 09:55:26 PM
Thanks for the reply.  As beefy as it is, you would think it’d be a super hard metal.  Replacement price is $190+ :o
Title: Re: Bolt not locking back on the last round
Post by: Hemiscorpius lepturus on October 29, 2019, 11:59:56 PM
actually, the softness of the metal makes it not brittle, same with the hammer, so they will not crack when they impact eachother, or when the bolt slams forward
Title: Re: Bolt not locking back on the last round
Post by: Manticore_Arms on November 03, 2019, 06:09:57 PM
Let's check a few things before writing that gun off.

First, pull back the bolt, push up on the bolt catch, let the bolt go forward slowly- does it lock the bolt open?  If it works, your most likely issue is mags.

Second, what mags are you using?  Some mags don't seem to reliably lock the bolt back, or when heavily used don't seem to have enough spring pressure to lock the bolt back.



The rounding on the front edge of that bolt looks to be factory done, there is finish over it.  I haven't pulled the bolts on all our in house guns to check against your pic, but lets assume it left the factory that way and check #1 and #2 before writing the bolt off as bad.

Sven
Manticore Arms
Title: Re: Bolt not locking back on the last round
Post by: bravo5two on November 04, 2019, 07:59:43 AM
Just an FYI, mine is the Gen 1 pistol and its bolt's forward edges are sharp 90 degrees, not even a little radius.
Title: Re: Bolt not locking back on the last round
Post by: SilverBullet76 on November 04, 2019, 05:22:06 PM
I’m using two 20 round factory mags.  It does lock back when I push the bolt catch up.  I need to try brand new mags coz  I bought two used manticore mags from some guy and didn’t work either.
Title: Re: Bolt not locking back on the last round
Post by: SilverBullet76 on November 04, 2019, 05:23:51 PM
Just an FYI, mine is the Gen 1 pistol and its bolt's forward edges are sharp 90 degrees, not even a little radius.
I was hoping that newer evo’s have the same bolt as mine to rule out the bolt is the problem and that I just need to use newer mags.
Title: Re: Bolt not locking back on the last round
Post by: SilverBullet76 on November 11, 2019, 08:43:05 PM
I got my magpul mag last week.  I took a picture and there's a difference between the magpul (brand new mag) and manticore and original cz 20 round mag.  The magpul one pushes the bolt catch up all the way where the inner elbow of the bolt catch is hitting the trigger unit casing, while the manticore and oem mag does not.  Bolt locks open with magpul when I rack and release it.  Granted I haven't shot it, but I don't see any reason why It wouldn't lock back.  Can anyone tell me if yours is the same?  Thanks!

(https://i.imgur.com/SWlRQZH.jpg?2)

(https://i.imgur.com/mStwgjn.jpg?1)
Title: Re: Bolt not locking back on the last round
Post by: SilverBullet76 on November 13, 2019, 10:45:05 AM
Anyone?
Title: Re: Bolt not locking back on the last round
Post by: Henny on November 18, 2019, 12:56:02 AM
Anyone?

I checked my 2019 made Scorpion. Both edges of my bolt are a perfect 90°.
Title: Re: Bolt not locking back on the last round
Post by: SilverBullet76 on November 18, 2019, 09:13:32 AM
Thanks!
Title: Re: Bolt not locking back on the last round
Post by: Manticore_Arms on November 18, 2019, 06:52:44 PM
Have you contacted CZ USA yet?
Title: Re: Bolt not locking back on the last round
Post by: biggerhammer on November 18, 2019, 08:11:08 PM
My 2017 and 2018 are both 90 degree, no radius.
Title: Re: Bolt not locking back on the last round
Post by: SilverBullet76 on November 19, 2019, 06:04:27 PM
I haven’t called cz yet only because I don’t have anything to compare it to as far as how high other evos’ bolt catch go when the mags are empty compare to mine.  Using magpul, the bolt catch go as high as it can and the bolt locks back.  Using used factory and manticore mags, the bolt catch doesn’t go high enough.  I appreciate all the replies though. 
Title: Re: Bolt not locking back on the last round
Post by: Trooper894 on November 19, 2019, 07:44:55 PM
It may be the way the light is hitting the edges/corners of the bolt, but to me it looks like someone took a file, then a stone to the corners of the bolt for whatever reason. The rounding of the corners does not appear to be even all the way across, like it was filed/stoned free hand. Perhaps someone thought it might facilitate removal of the bolt receiver for cleaning.
Just a further note. I have a 2018 produced bolt in a pistol and the corners are completely squared off. The bolt in my 2019 produced Micro has squared off corners also.
Title: Re: Bolt not locking back on the last round
Post by: Henny on November 20, 2019, 08:54:31 AM
I haven’t called cz yet only because I don’t have anything to compare it to as far as how high other evos’ bolt catch go when the mags are empty compare to mine.  Using magpul, the bolt catch go as high as it can and the bolt locks back.  Using used factory and manticore mags, the bolt catch doesn’t go high enough.  I appreciate all the replies though.


Here you go!  Something to compare yours to!

My bolt:

(https://imgur.com/QcoWpo4)

Magazine catch with CZ 30 round magazine.

(https://imgur.com/fwkWlru)

Magazine catch with AK magazine.

(https://imgur.com/K9xRFFJ)


Hmm, in not sure why I can’t post photos?  Yes, I’m using the image tag?  Do I have to have a certain number of posts?


Here’s the links for them.

https://imgur.com/QcoWpo4

https://imgur.com/fwkWlru

https://imgur.com/K9xRFFJ




Title: Re: Bolt not locking back on the last round
Post by: SilverBullet76 on November 20, 2019, 11:51:16 AM
Thanks guys for the replies.  Henny, the pictures have been very helpful.  I will contact cz.  There obviously is something wrong with my evo.

As for posting pictures.  I had trouble doing it myself.  I couldn’t do it with mobile devices so I switched to desktop.  Go to your imgur accnt.  Hover your mouse to your accnt and you should see a selection of drop down and click images.  Clink on the picture you wanna post.  Hit copy next to “direct link.”  You can now paste the copied link here, highlight the link and click the mona lisa icon above the emojis, click post and you’re done. 
Title: Re: Bolt not locking back on the last round
Post by: eastman on November 20, 2019, 08:49:24 PM
the img tags didn't specify the .jpg image, so it tried to reference the page with the same name. Sized them for display to 900 wide

I haven’t called cz yet only because I don’t have anything to compare it to as far as how high other evos’ bolt catch go when the mags are empty compare to mine.  Using magpul, the bolt catch go as high as it can and the bolt locks back.  Using used factory and manticore mags, the bolt catch doesn’t go high enough.  I appreciate all the replies though.


Here you go!  Something to compare yours to!

My bolt:

(https://imgur.com/QcoWpo4.jpg)

Magazine catch with CZ 30 round magazine.

(https://imgur.com/fwkWlru.jpg)

Magazine catch with AK magazine.

(https://imgur.com/K9xRFFJ.jpg)


Hmm, in not sure why I can’t post photos?  Yes, I’m using the image tag?  Do I have to have a certain number of posts?


Here’s the links for them.

https://imgur.com/QcoWpo4

https://imgur.com/fwkWlru

https://imgur.com/K9xRFFJ
Title: Re: Bolt not locking back on the last round
Post by: SilverBullet76 on November 21, 2019, 03:13:41 PM
Thanks eastman!
Title: Re: Bolt not locking back on the last round
Post by: boss281 on November 29, 2019, 06:52:29 PM
Glad I saw this thread. I have a brand new Scorpion pistol and put about 200 rds 115g Speer Lawman through factory 20 and 30 round magazines and the bolt has NEVER locked back. Interesting...
Title: Re: Bolt not locking back on the last round
Post by: SilverBullet76 on December 01, 2019, 01:06:39 PM
What model do you have and when did you purchase yours?  Right now my scorpion is at cz.  Hope it gets fixed.  I also noticed excessive wear on the hammer.  Their email said 4-6 weeks turnaround. 
Title: Re: Bolt not locking back on the last round
Post by: boss281 on December 01, 2019, 01:37:59 PM
Glad I saw this thread. I have a brand new Scorpion pistol and put about 200 rds 115g Speer Lawman through factory 20 and 30 round magazines and the bolt has NEVER locked back. Interesting...

Update: I was very surprised to see how fouled the gun after 4 boxes of ammo, so I field stripped it and cleaned it really good (I did a basic clean and lube when I first received it as well.

Since I had updated the trigger, trigger springs, right side safety and magazine release, I took those all apart as well, cleaned and lightly lubed moving metal parts where applicable.

Upon reassembly and light lube, the bolt is holding back properly.  Must have not quite put something back together properly although the pistol shot fine other than the bolt hold back issue. Put an inexpensive Holosun red dot on it, cowitnessed with the fixed sights. Happy now, will see how it performs at a Level 1 Steel Challenge match. 
Title: Re: Bolt not locking back on the last round
Post by: SilverBullet76 on December 01, 2019, 03:07:07 PM
Glad I saw this thread. I have a brand new Scorpion pistol and put about 200 rds 115g Speer Lawman through factory 20 and 30 round magazines and the bolt has NEVER locked back. Interesting...

Update: I was very surprised to see how fouled the gun after 4 boxes of ammo, so I field stripped it and cleaned it really good (I did a basic clean and lube when I first received it as well.

Since I had updated the trigger, trigger springs, right side safety and magazine release, I took those all apart as well, cleaned and lightly lubed moving metal parts where applicable.

Upon reassembly and light lube, the bolt is holding back properly.  Must have not quite put something back together properly although the pistol shot fine other than the bolt hold back issue. Put an inexpensive Holosun red dot on it, cowitnessed with the fixed sights. Happy now, will see how it performs at a Level 1 Steel Challenge match.
That’s good!  Mine would lock back, using the factory mag, if I racked and slowly release the charging handle, but when I do the HK slap or shoot it, I could not get the bolt to lock back.  Anyway, 1 week has passed and I only have 3-5 more weeks to get it back.  Can’t wait.   
Title: Re: Bolt not locking back on the last round
Post by: SilverBullet76 on January 07, 2020, 05:25:23 PM
Update.  I just received an email saying it’s been repaired.  Not sure how adjusting the breech face would fix the bolt not locking back.  Below is what they emailed me.

Description: bolt not locking back

Work Performed: Adjusted breech face lead in test fired good.
Title: Re: Bolt not locking back on the last round
Post by: SilverBullet76 on January 15, 2020, 04:55:32 PM
Just received the evo and the bolt locks back when I rack and release it majually.  I haven’t shot it yet, but see no reason why it wouldn’t lock back.  Thanks guys for all your input.