The trigger group is very AK-47 inspired so disassembly and assembly is not a big deal.  Drilling out that nasty weld in the World Screw is a pain for most.



 

I keep hearing horror stories about the spring. Getting it locked into the channel so to speak.

Wasn't a problem on mine...BUT, I will tell you what WAS a problem:  When you yank the mag release to replace it with an aftermarket unit or just to do any maintenance, be careful where the "seating end" of the mag release spring goes on the trigger pack....it is actually reallllly easy to place it on the wrong shelf in the housing and crush it like a bug.



 

Took about 10 mins and two curse words. Done

NICE,

 

Have you heard back from CZ yet about your inquiries?

Email sent today.  Thank you for reminding me to do that.



 

UPDATE 08/11/2016





Welp....here I am again.
So, my predictions were fairly accurate:  I cured a huge amount of the bullets getting caught on the pin lobes of the trigger group.  Feeding of Remington ( yellow and green box ) were both stellar as always.  Those are my control.
Winchester and Aguila ran on several orders of magnitude better.....BUT I still had issues with that damn extractor not snapping over the rims from time to time.  I had TWO malfs that were roll over failures...which is a bit odd but I'll dress the bottom lead in of the chamber radius and polish the chamber.
That extractor spring is so damn strong that it makes a dual o-ring AR-10 extractor spring setup look wimpy.  It's just too damn strong....it's stupid.  I'll switch to that softer spring I have and focus only on Winchester and Aguila next week as I can't get Remington or Blazer Brass to jam at all.
98 percent of the failures I had were simply of the extractor not being able to snap over the rim.  The other two were roll over / lead in feed failures.  The "good news" is that they were centralized and not focused on the left or right sides of the mag.  So, even though the spring I am going to use is a bit weak for my tastes, I want to see if I can prove the concept that the extractor spring is the biggest culprit.
Why do I keep focusing on this?  Because I can put 50 rounds into a group the size of a silver dollar....shooting really, really quickly.
NOTE:  I haven't found a 115 or 124 that doesn't shoot like a laser through this gun.
I think I almost have this problem licked.  Next week will tell.



NOTE:  I am working a a "FINAL THOUGHTS" post that I will plce in this thread.  I have largely been working on the negatives but there are a lot of positives, too.  I'll make sure the post is clearly easy to find.

Thanks for chronicling your efforts; I haven't been able to get to the range in a few weeks to run similar diagnostics on mine, but it was also having the occasional bent round--and now I know where to look and what to do

You are very welcome.  I'll be doing the rollover and polishing the chamber tomorrow.  I'll also put in the temporary "soft spring" to see how it runs.  THAT should be interesting.



I did some more investigating tonight and it certainly appears that rollover and extractor snap over are my culprits now.  Let's see if I can lick this yet.



Also:  NO email response from CZ.  Surprise.  I've not heard a lot of great stuff about their customer service.



Also Also:  Stock hinge pin is walking.  BUT: I know if they put a taper pin in, some doofus would try to knock it out the wrong way.  Sigh....another mod to be made.



 

Okay, I have polished the lead ins on the bolt face, dressed the extractor again and changed the spring to my "soft spring".  I can now softly chamber a round and the extractor snaps right over the case head.  Extraction, like my previous tests is still positive.  How that will work under full recoil is anyone's guess.



Tomorrow I am going to dress the rollover angle on the lead in to the chamber and I am also going to polish the top of the chamber.  I'll also lightly re-polish the feed ramp.



Initial testing shows an even smoother feed than before...hopefully after I finish the feed ramp and chamber, it will run even smoother.



I have decided to go for a test tomorrow.  I am going to run all of my problem child ammo first.  We'll see how it goes.



Will report tomorrow.

Ive had the pistol version since last September and its been SBRd since December. With nearly 2k rounds its been flawless. Not a single issue.

As far as recoil is concerned id say it mild. I typically shoot 147gr and 115. Stupid accurate. Trigger with the HBI springs is acceptable. Its a pccc not a bolt gun.

I have 2 mags loaded with 30 for almost a year now. No cracked feed lips. My barrel nut came right off when i had it rethreaded.

There is a FB grouo dedicated to this gun. Its not that people havent had issues, but the negative experiences touted here do not seem to be the norm gi en the 4k membership of the FB group.

I have noticed that.  I seems to have a more negative experience than what seems to be the norm.  However, it might be a good thing for this info to be out there for people who do have issues.

Mods are complete.  Dry run seems very promising.....let's see what happens.  

SUCCESS!!!!  



It was apparently 109°F in the shade today so I took the opportunity to give this gun a full test.  I ran that bitch SMOKING hot....and it ran 100 percent!!!!



I ran over 500 rounds through it in less than two hours.  Accuracy was still excellent, reliability was perfect........and I even cracked a magazine without dropping it! ....but that mag still RAN!!!!  ( Yes, it's going back )



So, working the rollover on the chamber throat, re polishing and cleaning up the feed ramp some more and polishing the top of the chamber ALONG WITH the "weaker" extractor spring did the trick.



It's funny, I really thought that spring wouldn't be able to hold up to a dirty gun....but hot AND filthy it ran fantastic!!!!  I did do a dry cycling run at home and still discovered that bolt needs to "fly home" to get that snap over...but not nearly like the OEM spring.  So, I ran it with the bolt release just like an AR and it just ran like a friggen' sewing machine.



NOW I finally feel like I can do a fairly objective and thorough write up on this to finish up this project. My next project is going to be the new Auto Mag...but that is a ways out yet.  Write up to follow at some point in the near future.

Sounds like it ran great even with the Aguila ammo!

Glad to hear you had success finally..................I hadn't heard about a new AutoMag................might need to check into those

The guys doing this are GOOD.  One industrialist and one top shelf firearms engineer with an incredible machining crew.  They are taking their time......they are really committed to combining today's technological abilities and the original design to make one hell of a pistol.



Get your wallet a parachute.  



 

I'm curious, With Bolt does your CZ Scorpion Carbine has? I know the world Model intruded a cut out, for the added part that in the World Model receiver, to prevent the old bolts from working on them.  Just a guess but, if they changed the mass of the bolt, and not change the spring to accommodate the change in mass, might have caused the issue with the extractor not going over the case rim.



Pics from Jrad33: Form this Thread

New style on the left old style right.

Thank you for posting those pics.  I have the "lower mass" bolt.  You know, my malfs were so severe that I don't believe the mass had too much to do with it.





the more I think about it and the more I worked with the "weak" spring that I added, the more I wonder if somehow the OEM spring in my Evo was just plum not the right spring.  I mean, you couldn't even MOVE the extractor with your thumb....not exactly good for a push feed design.





I thought the weak spring would fail once the gun got ultra hot and filthy....but that was not the case...and I seriously pushed my luck with this gun.  My mods worked ( as a cohesive group ) however and the gun ran like a dream!!!

 

Yeah, I will have to wait on a bonus or sell my Hi Power practical and all it's mags................but, I have always wanted an Auto Mag.........

They are GREAT for shooting pool!!!!!  



Actually, truthfully, a properly made Auto Mag is the only true, viable magnum auto loader option that ever existed.  The Coonan is a close exception to that rule.



 

....annnnnnnd FINALLY.  I let the gun sit all dirty and filthy so it would get a bit "gummy"




ARF member Walther22lr and I took her back out again tonight and shot another 200 rounds with the help of a couple of cool strangers we met at the range.  ( we also shot our Walther's!!!  Walther's Walther PP in .22 ( oh yeah! ) and my P1.  That was fun, too!!!!





All guns ran like a damn TOP.  The CZ really shined tonight.




So, I am finally happy.  CZ even emailed me and claimed the hammer is just fine.  I'll remember to tell all of my other gun's hammers that it's okay to just look like crap.  That being said, function has not suffered from that end.  Who knows what I will do about it....get a new hammer?  I dunno.....and, the moment, don't care.  I'll do something, though.





Gun was accurate as always, easy to handle and just a hell of a lot of fun.





Gonna be frank....it was with the help of HB Industries and their components, some lathe time and a fun optic ( Vortex Spitfire AR ) and a single spring from Brownell's that made this gun come into its own.





I AM working on a my final write up....but need to add some photos and finish the text.





I have tested about ten of my thirty mags and one has cracked the feed lips, a 30 round US made magazine.  So far the rest of my test mags are good to go.  I will likely rotate one in and out as I go....but for now....my T and E is complete.





General opinion of this gun:





Love it.  It is easy to use, easy to maintain and accurate as all get out.  I am not convinced that, as a carbine, this weapon is durable enough for extreme field use or serious combat.  The clamshell construction, and overabundance of screws and a mediocre choice of metals ( not bad...just nothing to squeal about ) don't lend me a lot of confidence in the Scorpion's ability to take serious martial use.





BUT!  Buuuuut!  As a home defense or personal defense weapon with the European mags ( as it seems to be the U.S. ones that crack from what I have seen and understand ) using a good optic and buffering the usability with HB or SE or GHW parts.....it could VERY easily fill a great home defense piece or a general police PDW type weapon.  There are some things that still need to be fixed such as a positively locking ( in the closed position ) stock and he availability of mags that you KNOW will not crack.  ( .05 percent, my ass )





If you want something different than the hum drumness of the AR ( which is my favorite rifle design ) and want to play around with something that is easy and fun to work on and improve and personalize...the Evo, for the money, just can't be beat.

 

My understanding of the 30rd mags ordered from CZ-USA was that they were just US followers and floorplates on import mags. Am I mistaken?

My 2012 european mags cracked.
My only 2011 and later replacements 2015 mfg are fine.

20 rounders seems to be more prone to cracking since they're using 30 rounders springs

Good info, Guys.  Keep it coming!  My one (so far ) cracked mag is a 2015.

Hmm... I got 10 of the 30 rounders about a month ago. Most of them are Nov '15 manufacture, and the follower and floorplate are embossed "CZ USA".

I saw someone made a 3D printed 10 round extension you can put on the 20 rounders. If they came out with a marketed product, I'd probably get a couple just to make my two 20 rounders into 30 rounders.

I need to add some belated thanks to Walther22lr, here.  He has been really instrumental in helping me run this gun and get it to the success point.  Plus...he has nice Walthers!!!!  The 22lr PP with Stingers was just SWWWWEEEEEEET!





 

By they way, Frens, thank you for that info.



I am in the automotive industry and discussed this with a good buddy of mine who is an engineer par excellence. His feeling is that during the shot, the feed lip area of the mold may be pulling too much heat from the mix at times and the flow is not properly solidifying.  Essentially, some of the plastic is cooling faster than the rest and the mix is not bonding correctly across the entire matrix.  Just a quick theory and strictly anecdotal.



 

I dont know. I've worked in the polymer injenction industry for a few years and this kind of polymers are usually molded at temp higher than 250C depending on the kind of polymer used.. So i guess they should handle 140C for a short period of time quite easily.. Im not sure the feed lips area get so hot during firing

I meant during the original injection molding.  It is strictly a theroy.

 

Could be.
A well Made mold should be designed to keep critical areas cooler or hotter depending on the shape/material/etc

Seems a weird issue after years of use by the mil.. I wonder if the propetary bren mags have the same problem

A very good question.