CZ USA 30 Rnd windowed mag issue

[Alkrinos]

Hi fellow scorpion owners,

Any of you have issues with CZ USA windowed mags not holding the bolt back?


After a very long wait, I've finally managed to get my hands on 5 brand new CZ USA windowed mags (30 rounders).

The problem is the mags won't hold the bolt open on last round / empty mag (issue is the same with all five mags I purchased).

Well, to be more precise, the magazine engage the bolt catch and hold the bolt back but as soon as i extract the magazine the bolt violently closes.

After analyzing closely and tinkering around I found the problem:

For some reason, the magazine follower tab that makes contact with and push the bolt catch up is too short by 1 or 1.5 mm.

Because of that the bolt catch does not fully engage and spring tension is the only thing keeping the bold open, so as soon as I pull out the magazine the bold close.


Some additional information:

• Magazine spring tension is not to blame here. If I put a small piece of folded paper on top of the follower's tab (to add some extra height), the bold catch fully engages.
• I live in Europe, so my scorpion evo is Czech made (similar to the early US gens without 1/2x28 thread).
  I don't think there is any difference with the US version when it comes to bolt catch specs but so far this is the only logic explanation i can find.
• The magazine have a white follower, first time I see this... All the pics on the internet show black followers for windowed mags. I'm positive they are genuine though, I bought it from brownells local branch, and they are directly imported from the warehouses in the US.
• My scorpion have no custom parts or mods, everything is stock.
• If I lock the bolt back using the charging handle (MP5 style) the magazines will drop free. Also, no feeding issue so far.
• I have no issues with the OEM 10,20,30 rounds translucent mags.
• I printed a follower with a slightly longer tab on a 3D printer. Everything works fine (BHO, feeding, etc..) but I'm still a bit concerned about the relability when it comes to having a home-made 3D printed follower on a weapon.

Be aware that I'm living in Europe and it was a hassle to import those mags (they are restricted here) so I can't simply send it back to CZ USA.

So far the only solution I see is putting some epoxy on the top of the follower's tab to add the few millimeters that are missing... The thing is I'm not sure this will hold and be reliable.

This is very disappointing to have to modify brand new OEM magazines for them to work properly ... even more when you paid twice the price and had to wait almost a year to get them.

Any suggestion on how to fix this?

I'll appreciate any insight or help with this matter!


Thank you very much!

PS: I've tried other forums and even to contact CZ USA customer service directly to no avail (they seem to be famous for that). You are my last hope guys 

[Trooper894]

If they were my magazines my first operation would be to disassemble the magazines and look for a couple of things.
First, is the magazine spring installed correctly, if the magazine spring is rotated 180' the spring may not lift the follower properly. The
        very end of the spring should wrap around the FRONT of the follower
Second, look the follower over carefully and make sure there is no "molding flash" left that may be hindering the magazines from seating
            fully to the top of the magazine. Pay particular attention to the area around the little "post" on the left rear of the follower that
            engages the bolt hold open.
Third, look up into the top of the magazine to see if there is any "molding flash" or anything else in the magazine interior that could be
         hindering the follower from fully rising. Again pay attention to the top left rear corner of the magazine where the "hold open post" on
         the follower comes up through the magazine making sure that area is free of "molding flash" or burrs.
Of my last 6 of the black windowed magazines, 3 had the black followers and 3 had the white followers and all my work fine.

[Alkrinos]

Thanks for your help Trooper894!

I've indeed checked my 5 mags for some kind of "molding flash" or something hindering the follower from going fully to the top.
Sadly this is not coming from this kind of issue, it seems the follower is seating properly and everything is in order.

The "post" fits the "recess" on the back of the magazine (it's just sliglty bend outward due to spring tension pushing the round follower's top against the mag's lips).

When compared to the translucent mags I own(which work perfectly) the "post" seats in the same type of "recess" so i guess it's how it's supposed to be.

I don't have a caliper at hand to measure the height from top of the "post" to the top of the magazine lips on the two type of magazines (Windowed and translucent), but if you have the opportunity to get this measurement I would gladly have it for further comparison with mine.

One thing i noticed is that the windowed magazine follower wobble a little more than the one in the translucent magazine but I think this is by design.

The only logical explanation would be that Czech and US made bolt catches specs/tolerances are slighlty different from each other but I find it very weird!

Here are some pics, in case I'm missing something obvious:


















Thanks again for your help.

[Trooper894]

Alkrinos, in looking at your photos, your magazine springs are rotated 180' off from mine or your follower is rotated 180' different than all of mine. (May not make any difference.) Mine have the very end of the spring ending on the same side (left) as the bolt lock post on the follower. Sorry I don't have a means to post photos.

I've been very lucky. I've got 2 different Scorpions and I've got 12 of the CZ 30rd brown translucent mags and 6 of the CZ black heavy duty windowed mags and all my mags will securely lock the bolt catch back so that it remains locked back when the mags are removed. I just pulled both my Scorpions out and my black heavy duty magazines out to double check a few things. I misspoke about my followers. 2 mags have black followers and I cannot find any date code stamp on those mags. 4 of the mags have white followers and a date code stamped on the back spine of 5/18 or 6/18. I also have 30 aftermarket magazines from Palmetto State Armory that are available to us here in the USA and all of those mags also work perfectly.

One other thought. Can you pull the follower out of a working translucent magazine and put it in the black windowed mags to see if the mags then function properly. I would also try to see if the "new" followers will work in your older translucent mags. Just an experiment to try and narrow down where the issue is. I will try to get you some measurements as soon as I can get to my shop to get my calipers, it's raining buckets here right now. (First real rain we've seen here in 2 months, so I'm not complaining.)

[Trooper894]

Alkrinos
I measured the distance from the top of the magazine (top rear feedlip area-immediately above the follower post) to the top of the post on all 6 of my black heavy duty windowed magazines. #1 black follower 12.47mm, #2 black follower 12.57mm, #3 white follower 12.46mm, #4 white follower 12.49mm, #5 white follower 12.52mm, #6 white follower 12.50mm. (+/- .02mm)
The 2 black followers have a squared off skirt immediately below the post and that height was #1 =12.26mm tall, #2 = 12.28mm tall. All the white followers have the same angled area below the post as yours which made it impossible to get an accurate measurement on the height of the post from the bottom of the skirt.

[motorolanut]

PSA Mags are a HUGE bang for the buck.  I ditched all my CZ factory and Manticores going to the PSAs exclusively.

[Alkrinos]

Alkrinos
I measured the distance from the top of the magazine (top rear feedlip area-immediately above the follower post) to the top of the post on all 6 of my black heavy duty windowed magazines. #1 black follower 12.47mm, #2 black follower 12.57mm, #3 white follower 12.46mm, #4 white follower 12.49mm, #5 white follower 12.52mm, #6 white follower 12.50mm. (+/- .02mm)
The 2 black followers have a squared off skirt immediately below the post and that height was #1 =12.26mm tall, #2 = 12.28mm tall. All the white followers have the same angled area below the post as yours which made it impossible to get an accurate measurement on the height of the post from the bottom of the skirt.

Thank you very much again for your time and help Trooper894!

I'll compare your measurement with mine as soon as i can access my workshop (bleep covid...).