CZ Scorpion Pistol to SBR

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Scott B.
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CZ Scorpion Pistol to SBR

#1

Post by Scott B. » Sun Mar 19, 2017 10:45 am

I've previously posted about my CZ Scorpion EVO 3 S1 Carbine (http://www.texaschlforum.com/viewtopic.php?f=87&t=84560). This post will be about the pistol version and its journey to becoming an SBR (Short Barreled Rifle).

Here's what you start out with, a 9mm pistol:

Image

To convert to an SBR, you'll need to pay $200 and submit your Form 1 paperwork. In about 8 ~ 12 months (these days) you'll get the tax stamp back and permission to make your pistol into an SBR. But wait, that's not all you have to do.

922r compliance.

There are officially 16 parts in the Scorpion pistol. The pistol is made in the Czech republic. 922r is a rule relating to a fun law (27 CFR 478.39) regarding the manufacture of a rifle from a list of 10 foreign made parts if the end result is a 'non-sporting' rifle.

CZ sells a 922r compliance kit. It consists of the following US made parts: 2- Mag bases 2- Mag followers 1- Disconnector 1- Trigger 1- Pistol Grip 1- Compensator. 8 parts replaced of the 16.

Replace those parts and you're in compliance with 922r. I am unaware of any enforcement of 922r at the individual consumer level, but comply with it we must.

For me to make an SBR I go a little different route. I have a type 07 FFL and an 02 SOT (special occupational tax). To make an SBR I simply file a Form 2 notification to ATF and appropriately engrave the item with company name and location.

Then I comply with 922r and slap a stock on the pistol. Here it is with US parts taken from my carbine and made 922 compliant:

Image

First major upgrade I did was change out the handguard. I dislike the stock one because it has the cheese graters (rails) molded right into the piece. The replacement is from HB Industries, is US made aluminum, has mlock slots and deletes the CZ barrel nut. You can also toss the irritating little ambidextrous sling eyelets that tend to rattle.

There is one minor flaw with this handguard. It's aluminum as stated, but so to is the nice replacement charging handle. Aluminum on aluminum moving parts is not so great. HB actually suggests that you run the stock charging handle as it's part polymer. Something to tackle down the road.

As it's going to be when I shoot a carbine match later today:

Image

Next change will be an Apex pistol grip that's a more vertical style that I hope will be a little more comfortable. The stock CZ grip isn't bad, but does get a little slick in the south Texas heat.

I've got a Gemtech GM-9 suppressor coming that's going to complete the SBR, for now. I am going to have the barrel shortened about a 1/4 inch and re-threaded to 1/2-28. It currently sports 1/2-28 threads, but they sit right in front of M18-1 metric threads from the old barrel nut. The 1/2-28 threads also look really short to me and I'm not 100% certain the suppressor will fully seat.

More pictures as things change. Questions? Fire away.
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Re: CZ Scorpion Pistol to SBR

#2

Post by Scott B. » Mon Mar 20, 2017 6:01 pm

Some of the Scorpion barrel nuts can be real challenges to get off. Using a barrel nut tool, offset wrench, I was easily able to clear the handguard and turn the nut.

Luckily there were only 2 or 3 threads w/ locktite on them. Cleaned right up with steel brush.

Image

Those are the 1/2-28 threads front, and the M18-1 threads of the barrel nut behind. I'm going to have that trimmed up and rethreaded.

Did try a new pistol grip, but didn't work for me. Made by Apex. It's a fine pistol grip, but once you shoulder the gun, the angle turns uncomfortable. This surprised me because I like my AR pistol grips to be more vertical than the A2 style. Switched back to the CZ grip. It's not aesthetically pleasing to me, and gets real slick in the summer, but I can work on that last bit with some skater tape.

This image shows the angle change of the Apex grip (on top):

Image

I'm fighting a powerful urge to paint this thing Coyote Brown (I have too many black guns as it is).
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Re: CZ Scorpion Pistol to SBR

#3

Post by SigM4 » Tue Mar 21, 2017 4:35 pm

Very nice. I'm waiting on my Form 1 filed back in early July to convert my carbine to an SBR. I have a HBI handguard like yours (though flat not slanted front) and a Yeti Werks grip (way more comfortable than the CZ grip). I'm planning on having a pistol barrel cut down to about 4.5" and threaded 1/2x28 for a three lug adaptor next time we're down in DFW (Class 3 Machining. I'd love to have the three lug machined right into the barrel, but not quite enough OD to do it. This should tuck my Octane or Obsidian neatly under the handguard. I'll post pics when its complete, shouldn't be too long before I have the stamp in hand.

Also, did you see where Prepper Gun Shop has the Manticore designed 32-round smoke mags with the metal feed lips in-stock? I've got a couple of these headed my way as we speak.
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Re: CZ Scorpion Pistol to SBR

#4

Post by Scott B. » Tue Mar 21, 2017 9:10 pm

You must be climbing the walls with that stamp being so close to being issued.

Ordered a couple of mags as well. Just got my shipping notice from Prepper.

Which Yeti grip did you go with? I've looked at the Switchback with some interest.

I'm torn about having the barrel cut down any more, but I do like the idea of tucking the suppressor under the handguard. With the HB handguard mounting system, it's not like I couldn't pull it off if had trouble getting the suppressor off for cleaning.

What I'd really like to know is at what length accuracy starts to open up?
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Re: CZ Scorpion Pistol to SBR

#5

Post by SigM4 » Wed Mar 22, 2017 6:21 am

I opted for the Switchback because I wasn't sure which profile I wanted. Turns out I like the "no bump" backstrap.

HBI has tested and guarantees functionality down to 5.5" to match up with their K handguards. Several folks over on CZ forum have gone down to 4.5" without issue. As to the accuracy I'm interested as well, at least out to ~50 yards or so. Beyond that as long as I can hit a man-sized target at 100 yards or so that's fine with me.

I have numerous other SBRs (a 12.5" .308 being my newest) to play with for now, but yes, I can't want to have a 9mm to add into the mix.
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Re: CZ Scorpion Pistol to SBR

#6

Post by Scott B. » Wed Mar 22, 2017 9:16 am

If the Switchbacks come back in stock, I'm going to grab one.

12.5" 308 sounds pretty interesting!

I've got a 11.5 and a 7.5, both 556. Thought briefly about an SBS can't find any real reason I need one. However, I am giving serious consideration to a K version MPX SBR that's been flirting w/ me. Perhaps an end-of-year bonus ;-)
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Re: CZ Scorpion Pistol to SBR

#7

Post by Scott B. » Wed Mar 22, 2017 4:11 pm

Took the Scorpion apart today so I could have the barrel sent out and rethreaded. Not much to it really. I would caution anyone taking theirs apart, the rear stock/button is under spring tension and will want to fly. Be gentle when prying the two flats apart and off the barrel trunnion. I could see somebody getting too aggressive there and regretting it.

Image

Old handguard pictured top for reference.
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Re: CZ Scorpion Pistol to SBR

#8

Post by rm9792 » Mon Mar 27, 2017 1:56 pm

I was under the impression that going NFA negated the 922r crap. When I researched threading a Beretta CX4 thats what I was told by the beretta forum.


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Re: CZ Scorpion Pistol to SBR

#9

Post by dragun » Tue Mar 28, 2017 7:58 pm

I really love your set up. It drives me crazy that we have to jump through those stupid hoops in order to have "comply" with moronic government regulations. :banghead:

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Re: CZ Scorpion Pistol to SBR

#10

Post by Scott B. » Tue Mar 28, 2017 9:34 pm

rm9792 wrote:I was under the impression that going NFA negated the 922r crap. When I researched threading a Beretta CX4 thats what I was told by the beretta forum.
Yeah, that's wrong. Unless you're talking MGs, different animal there. An SBR is still a rifle and manufacturers must comply, including individuals.
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Re: CZ Scorpion Pistol to SBR

#11

Post by Scott B. » Fri Apr 28, 2017 1:31 pm

Finished product.

Unsuppressed - has a little 2 3/4" comp just to get the muzzle blast past the handguard.

Image

Suppressed - GM-9 direct thread

Image

...and just because I was taking photos. An SBR I'd recently reconfigured more to my liking.

Image
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Re: CZ Scorpion Pistol to SBR

#12

Post by SigM4 » Fri Apr 28, 2017 8:21 pm

Scott B. wrote:
...and just because I was taking photos. An SBR I'd recently reconfigured more to my liking.

Image
Ha, I love it. I SBR'd one of those Aero Texas lowers too, just felt right.

I like the Scorpion as well. I had a pistol barrel cut down to the HBI Micro/k configuration length, and paired it up with a new trunion. Now I just need to have the extractor notch machined into the trunion/barrel. Once that's done I should have a nice short package. Can't wait.
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Re: CZ Scorpion Pistol to SBR

#13

Post by Scott B. » Mon Jun 04, 2018 6:40 pm

Updates to my Scorpion SBR since I first put it together:

Image

Went with a lower profile, quick-detach mount from Midwest Industries for the MRO red dot. Also added a Magpul MVG m-lock vertical grip. I don't run vertical grips on any of my ARs, but for this application it really works nicely. Very positive control over the gun and gets my hand off the metal handguard which I found can get a bit warm w/ a lot of shooting.

FWIW, duracoat is really durable stuff. The Belgian Brown I painted the gun w/ came out more maroon than I wanted. My Aggie bro-in-law loves it though. The stuff it would take to remove the duracoat would basically eat the polymer frame. I knocked it down a little with some light sanding. I may shoot another color over it for contrast.

Also added some texture to the Yeti Wurks pistol grip. Not a huge fan of this grip because it has a tendency to loosen up. Got that mostly solved but it bugs me. The texturing project was a bid to get some more mileage out of it before I try something else.

How:

Same process I've used before to add texture to some shotgun forends, but this used more material, seen here - http://www.texaschlforum.com/viewtopic. ... 5#p1081985

It's a concoction of Agraglas, some indelible black dye, and powered rubber. Agraglas is a two-part product normally used for bedding compound. Couple of drops of dye turns the paste mixture black. Then the powdered rubber gets blended in.

Prep like you would for any paint application and tape off what you don't want mucked up. Apply as desired, and please note that gloves, a shop apron, and throw-a-way applicators are strong advised. Take unused powder and cover the sticky Agraglas concoction. Press in if needed. Wait for it to start setting up before you attempt any molding, otherwise it's like trying to make Devil's Tower out of instant mashed.

Suggest you remove the tape before the compound gets too far along or you'll be chipping it off.


It's still one of the favorite shooters I own and is the one my friends or family always ask about when a range day comes around.
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Re: CZ Scorpion Pistol to SBR

#14

Post by SigM4 » Wed Jun 06, 2018 8:51 pm

^^^Nice. I know you said you’re not the biggest fan of the color, but I kind of like it. As you noted doing a light coat of a brown or something over top might not look too bad either.

Here’s my completed Scorpion SBR sporting the HBIndusties Micro K handguard and barrel profile.

Image

When I had the barrel (CZ Custom) chopped I also had it threaded so I could put a 3 lug adaptor on it. This lets me run a suppressor under a longer handguard (I also have the pistol length you have on yours) with ease.

Image

Only thing I still need is a low profile handstop and a Parker Mountain Machine rear sling mount.
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Re: CZ Scorpion Pistol to SBR

#15

Post by Scott B. » Wed Jun 06, 2018 9:23 pm

That K configuration is great. :thumbs2: Looks really good! I've actually got one of the CZ K pistols on order for my dad that we're going to SBR, looking forward to trying it out.

I do prefer the squared off handguard and wish I had gone that route instead.

On the Parker Mountain Machine QD socket, I've read that a few have snapped the polymer ringlet off the receiver with them. I'm not particularly worried, but am keeping an eye on it.
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