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Reader Eric writes:

You guys have reviewed the new CZ Scorpion and the SIG MPX separately. Is there a chance you could do a direct comparison between the two? That would be awesome.

I reviewed both the SIG SAUER MPX and the CZ Scorpion EVO 3 Pistol, and while I think I’m an impartial judge of the two guns I wanted to take that a step further. Following the release of these two guns, Jeremy S. purchased a Scorpion and I purchased my very own MPX. So I asked Jeremy to join me in a quick head-to-head review representing the Scorpion side of the argument, and I’ll be handling the MPX. Let’s get ready to rumble! . . .


General Appearance:
Scorpion (Jeremy S.): Angular and futuristic.

MPX (Nick): Sleek and familiar. It looks just like a midget AR-15.


Scorpion (Jeremy S.): Nearly everything visible on the outside is polymer. Barrel is cold hammer forged. Most other metal is forged or machined from bar stock. The bolt is over 1.4 lbs of solid steel.

MPX (Nick): The gun is mostly aluminum, with some steel inserts and other metal bits. It feels solid, not like the mostly plastic Scorpion.

Operating System:
Scorpion (Jeremy S.): Straight blowback. Simple and as reliable as it gets. The heavy bolt provides a nice delay to the action and definitely reduces gas and debris blockback through the breech.

MPX (Nick): The short stroke recoil system means the bolt is much lighter, and therefore there’s less moving mass to throw off your shot. It might complicate the operating bits somewhat, but it means a lighter spring in the gun and a lighter recoiling firearm in my opinion.


Scorpion (Jeremy S.): 10-, 20-, and 30-round magazines are available. Full MSRP for the 30-rounders is $19.95, and the other two run $17.95. All polymer except for the spring. Translucent body.


MPX (Nick): The gun ships with a 30 round magazine, 10 and 20 round versions coming soon. Mags are made by Lancer, a company who makes the only mags I trust for hunting. Like the Scorpion they are proprietary, but Lancer has a great track record for mag manufacturing. Way more expensive than the Scorpion though — $55 a pop.

Field Stripping & Cleaning:
Scorpion (Jeremy S.): Lock bolt back. Push out one captive pin by hand. Pull trigger housing off frame. Pull bolt out of frame. Done. Video.

MPX (Nick): If you’ve cleaned an AR-15, you can clean the MPX. Pull the rear takedown pin and the guts fall out. Pull the forward takedown pin and the handguards slide right off, revealing the barrel and gas system for an easy wipedown.


Available Options (barrel length, stock, etc):
Scorpion (Jeremy S.): Currently only available in pistol form with 7.72″ bbl. Optional AR-15 buffer tube adapter allows for mounting of a pistol arm brace or, with SBR registration, any AR-15 stock. CZ-USA will be selling a 922(r) compliance kit and the factory Scorpion Evo SMG stock in late summer. Once 922(r) compliance is assured, I expect CZ-USA will begin selling carbine versions and possibly factory SBRs. Maybe in time for Black Friday shopping?


MPX (Nick): Right now, the gun is only available in the 8″ barrel variety. You do, however, have the option of buying the gun with a customized pistol brace already attached that looks very slick. Coming soon, the gun will be available with a 4.5 inch barrel as well as a 16 inch option for those wanting a true rifle, and those barrels will be available as after-purchase options from SIG SAUER. Also coming soon are a collapsible MP5 style stock, as well as a side folding stock fresh from the factory. No pesky 922(r) considerations on this all-American gun. Changing your existing gun’s barrel length is as easy as pulling the forward takedown pin and unscrewing two hex screws, easier than any other gun I own. Other than the Ruger 10/22 Takedown.


Scorpion (Jeremy S.): Non-reciprocating, forward charging handle, which can be moved to either side of the gun. Can also be used to lock bolt to the rear and then released with an HK MP5 style palm bump. An additional, thumb-activated bolt release is used for after the gun locks back on empty. Ambidextrous magazine release is a paddle on each side of the front of the trigger guard. Accessible with strong hand index finger (for speed reload) or weak hand thumb (for tactical reload). Ambidextrous, AR-15 style safety comes standard, but CZ-USA also sells a right-side safety delete for those who prefer a sleeker and less obtrusive non-ambi layout. Reach to the trigger and safety is adjustable by means of a pistol grip that slides back and forth on a rail. Cool idea that I haven’t seen before.

MPX (Nick): The controls are identical to an AR-15, with some exceptions. There’s a magazine release on both sides of the gun to allow lefties as well as righties to drop the mag for speed reloads. The bolt release is also ambidextrous, with a control input on the right side of the gun. That not only makes it easy for lefties to drop the bolt but also for righties to do everything with just their trigger finger. The charging handle is akin to a standard AR-15 charging handle, but the shorter size and the design makes it incompatible with replacements already on the market. It does feel a little flimsy unfortunately, but its familiar and functions just fine.


Barrel Length:
Scorpion (Jeremy S.): 7.72″

MPX (Nick): 8 inches on the dot. Or 4.5 if you wait. Or 16 if you wait longer.

Scorpion (Jeremy S.): 4.33 lbs (pistol, no magazine)

MPX (Nick): 6.1 pounds with SB Tactical pistol brace attached.

Scorpion (Jeremy S.): 10-ish lbs of battle trigger. Plenty of take-up, an acceptably crisp break, rather gritty overall, solid reset. It’s definitely breaking in as I put more rounds through my example (edit: after about 500 rounds it is vastly improved. Lighter and smoother). On the bright side, it’s a drop-in unit so aftermarket replacements will be very easy to install and, yes, they’re already in the works!

MPX (Nick): Ugh. Squishy and a bit heavy, just like the original MP5 trigger. Definitely not the best feature of the gun, but acceptable.

Scorpion (Jeremy S.): From a sandbag rest at 25 yards with a 4x scope on it, I shot 6, 5-round groups with 5 brands of ammo and every last one of them was a single, ragged hole. The best group, which was shot with American Eagle 147-grain FMJ through the Liberty Mystic suppressor and is pictured below (HST round just for scale), was barely over a half inch. Yes, there are 5 rounds in that hole:


MPX (Nick): From 15 yards with some crappy ammo, the gun shoots damn near one-hole groups. I’d say the accuracy is pretty much a wash between the two guns.


“Rail Estate”:
Scorpion (Jeremy S.): Almost every part of the Scorp is covered in picatinny rail. The whole top of the receiver is railed, and that top rail continues onto the handguard. The other three sides of the handguard are railed as well. It even comes with a hand stop. With swappable receiver end plates, I wouldn’t be surprised if the aftermarket produces a selection of railed ones.

MPX (Nick): There’s a full length top Picatinny rail for your various sights and such, but the rest of the gun leaves it up to you. The MPX ships with a proprietary handguard and rail attachment system that lets the shooter choose whether they want a sleek slick-sided shooter or a rail-festooned porcupine. That makes for a comfortable gun, with the ability to change that at the drop of a hat. The gun ships with three rail sections, and a hand stop / sling mount already on the handguards. Proprietary rail sections make me uncomfortable, but the fact that it ships with a few sections is comforting.


Customize This:
Scorpion (Jeremy S.): Lots of “rail estate” obviously leaves options for customization fairly open. The Scorpion in pistol form also has 4 sling attachment rings on the receiver and ships with a receiver end plate that’s slotted in various ways for a strap sling. Swappable end plates make for lots of possibilities. At current, the choices are the slotted sling plate that ships with it and the AR-15 buffer tube adapter plate, but this same mounting system is how the factory folding stock attaches and, as mentioned, I’m sure the aftermarket is going to have fun with the possibilities (edit: Manticore Arms already has a prototype telescoping stock).

No aftermarket options for pistol grips yet, but it’s a simple polymer affair so I’m sure that will come. The ability to slide the grip forwards and back to adjust for trigger reach distance is great. Charging handle side can be swapped, and there are already two different safety lever options. On the negative side, the 18×1 mm RH barrel threading isn’t something we’ve had in the U.S. so there was zero support for it. Fortunately, suppressor manufacturers have already responded with mounts and thread pitch adapters, and since 18×1 is a lot larger than 1/2×28, a gunsmith could re-thread your barrel.

Apparently if the Scorp is a big success, factory 1/2×28 versions for the U.S. market are possible. Although the Scorpion doesn’t use a standard AR-15 trigger unit, which sure would have been nice, it is a self-contained, drop-in FCG and that’s going to make aftermarket replacement a simple affair. It takes me about 2 minutes to remove the FCG from the gun.

MPX (Nick): The Scorpion has a proprietary swappable end plate, but SIG SAUER put a standard Picatinny rail on the end to let end users put whatever they want on the gun. Rock River Arms already makes a side-folding stock for a similar Picatinny mount that is on the market (which I have ordered for my MPX) and others are available as well, with SIG SAUER’s own stocks coming soon. The easily swappable handguards and barrel make the gun very appealing for tinkerers as well, allowing end users to do cool things like extend the handguards over a silencer to increase rail space while keeping the gun as compact as possible.

UPDATE: Rock River Arms has refused to sell me a stock for this gun. Their owner claims that every sale of their stock MUST be accompanied by an ATF Form 1, which is a requirement that I have never seen before from a manufacturer. So they have refused to take my money, and I’ll just go buy it elsewhere. Stay tuned.

The barrel is threaded in the standard SIG SAUER 13.5×1 metric left hand thread, which is a common threading that is already available on the market here in the US and commonly available even for AAC’s ASAP piston system. In short, not only is the MPX going to have tons of options from the factory, but the end user can change damn near everything on their existing gun and aftermarket parts are already widely available.


Included Optics:
Scorpion (Jeremy S.): The factory iron sights on the Scorpion are pretty freaking sweet and I hope CZ-USA begins selling them separately! They’re steel, quality is top notch, the rear sight has four apertures that spin one to the next, and the front appears to accept a standard AR front sight post. The front is adjustable for elevation and the rear for windage. They mount on a standard picatinny rail. On the downside, they’re low and somewhat sleek, meaning they won’t co-witness at a normal AR height. They do co-witness with a small red dot sans riser, though, which happens to be the ideal height for optics with an SBR’d Scorp.

MPX (Nick): A set of flip-up iron sights comes on the gun from the factory along that top Picatinny rail. These all-metal sights are adjustable for elevation as well as windage, and they are very chunky to allow easy deployment and retraction. They are designed for standard AR-15 heights, meaning an SBR’ed MPX will see the sights perfectly aligned with your eye.

OtherCrap Included in the Box:
Scorpion (Jeremy S.): bore snake for cleaning, two magazines, sight adjustment tool, manual & warranty info, accuracy target, gun lock.

MPX (Nick): Three rail sections. A full mil-spec cleaning kit. A bottle of lubricating oil. A QD single point sling. Once 30-round magazine. And a gun lock. Oh, and “the box” in this case is a proper polymer gun case with a foam insert precision cut to keep the MPX securely in place. Its actually a very useful gun case, and looks great to boot.

Scorpion (Jeremy S.): 5-year limited warranty. (All CZ-USA firearms are warranted to be free from defects in material and workmanship for one (1) year on wooden parts and surface treatment and five (5) years on other parts to the original purchaser.)

MPX (Nick): LIFETIME limited warranty from SIG SAUER. If your gun has any manufacturing defects they will happily fix it for you. The warranty only extends to the lifetime of the original purchaser, so make sure your 18 year old son buys the gun and not your grandfather.

Scorpion (Jeremy S.): MSRP $849

MPX (Nick): MSRP $1,648 with brace, $1,378 without.


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    • When in doubt, merchants and FFLs go into safe mode. They’d rather frustrate a customer than have their doors kicked in by overzealous ATF thugs. Result? Mass confusion and nervousness. Everyone is a little afraid to buy and sell guns, which is exactly the chilling effect regarding gun purchases and use that the .gov desires.

    • At $1650 I have to ask whether a pistol caliber carbine is better than I could get out of an AR build at that price.

      I like the MPX a lot, but at that price I don’t see the value when I could have a very nice rifle caliber carbine or a pile of leftover cash and a pistol caliber carbine that shares magazines with something I own (e.g., CX4, Sub-2000).

    • It’s really 850 vs 1350. The 1650 version includes the folding stock with the Sig brace, the 1350 version is the straight up pistol that is most comparable to the Scorpion. Could you make an equally nice 9mm AR carbine at that price? Absolutely. Does it have a lifetime warranty? No. Does it look a little weird with its Glock or Colt mags instead of these sexier looking ones? Yes. Does it come out of the box, no assembly required? No. Is it fully customized for the format? These are. Do any of these matter enough or are they worth a couple hundred dollars to you? That question I can’t answer. I love my MPX though.

    • Don’t forget the Mechtech stainless steel uppers. Those seem pretty cool as well. And the 10mm hits pretty darn hard out of a 16″ barrel. Since I “can’t” have an SBR, my “pistol caliber carbine” will consist of 20rd Sig 226 TacOps, 34 round 9mm Glock mags, and maybe a MechTech upper.

    • In short, yes. If the trigger fits a regular AR, it will fit an MPX. I remember watching a video on Youtube of someone running an MPX with a Tac-Con “assisted reset” trigger. Pretty sweet combination.

    • Yes, I put a Geiselle SSA in my MPX last weekend and it works perfectly. Nick should have mentioned this in his trigger section. The standard trigger looks, feels… is, a standard mil spec AR trigger.

  1. I think you need to do a full on pistol caliber carbine comparo, like the muzzle brake fest you guys just did.

    Bring in a bunch a pistol cal ARs, Beretta CX4, Just Right Carbine, maybe even some of those glock-in-a-plastic-shell jobbies as well. Maybe even a PS90 to be the odd man out.

    On a side note, as silly as the idea is, does owning a “pistol” and ordering a stock for it make constructive intent, or would they have to be in the same house/safe/within in 20ft of each other? I’m guessing you’ve likely already filed the SBR paperwork, but still. I’d like to think the ATF is busy actually spending my tax dollars on useful “police” operations, but they do seem to love them some low hanging fruit.

    • If you don’t own something else that the stock can legally attach to then, yeah, possession of a stock for a pistol would be considered “constructive possession.”

      • Not exactly black, and white, there is a shade of grey.

        Do you have a buffer tube, or whatever piece is required to attach said stock? If not, then no constructive possession can be proven.

      • Not without a buffer tube, or other method of attachment. It isn’t constructive possession, just because I have a MOE, or UBR in my house, and a pistol.

  2. For the $$$, the MPX should have been built with a side charging handle. That’s my only gripe with it.

  3. I like the way you guys did this. It reduces the “single perspective” bias that we all have. Good job. I’m still getting a Tavor before dropping the same account of money on a pistol carbine AR though.

  4. It would be nice if the side rails on the Scorpion were removable. It would be slicker, and look more “futurey” in my opinion. That being said I live in CA so I’ll be taking my jealous rage with me as I crawl back under the progressive boots.

    • At least you’ll be able to get the carbine version of either of these with the help of a mag lock. I have one of the 10-round mags for the Scorp and while I don’t see any reason why I’ll ever actually use it, it does look cute and stubby in the magwell hahaha …and makes things easier for residents of a handful of states…

      BTW RE the side rails, that front handguard is easily removable so hopefully the aftermarket will respond with various replacement pieces. As Manticore Arms has already taken an interest w/ the Scorp and one of the first things they did for the Tavor was handguard replacements, I wouldn’t be surprised if this is on their list. My ideal replacement would be something extended that will fit over the Liberty Mystic and give it that integrally-suppressed look plus allow me to hold it w/ my support hand farther forwards.

  5. Price really will define this battle at the end if the day, really, considering one can almost buy two Evo’s for the price of one MPX. Not only that, the Evo is already a proven and capable submachine gun. Sig MPX still has to go through Sig’s end user beta test.

    Personally speaking? I’m waiting for the POF 9mm toy

    • I’m on their list for a loaner. If the gas bleed thing is what I think it is and I can run cheap 115 grain ammo while keeping it subsonic, I’m going to be a big fan of the POF piece. Pending other details like price, etc…

  6. I’ve been having a blast reviewing a Scorpion myself, and have already detail stripped it and documented the process of overhauling the trigger. I’ve had a pretty deep backlog the last couple weeks, so I won’t be able to post up a guide for it for a while yet. It’s very straightforward though, as you’d expect given the ease in which you can pop out the fire control pack.

  7. The Sig costs twice as much and the mags for it cost more than twice as much as the CZ mags.
    Not worth.
    Perhaps if Sig released the MPX in the era of jenky AR-15 9mm conversions, it would have been a hit. However, now with the CZ scorpion and many other options, it is not worth the high price tag.

  8. geez so much plastic, just stay away from heat, fire and you’re fine…while the uzi [and probably the orig. .32acp scorpion] weren’t accurate, they sure as heck would survive better in a mishap, conflict or war…when I saw article of course I said Sig, but read the prices and it’s ‘maybe the CZ’…you’d do better sticking a glock with extended barrel in one of those $300 plastic-&-rails RONI or FAB defense subgun pdw kit shells.

      • The CZ EVO has been being used in modern times by active military forces, and S.W.A.T. style teams and been in theater by ally military’s and semi, 3rnd, and full auto. And has held up, while the Sig has many just semi private problems (just have shut it down. Track record says all, opinions mean nothing when proven ability says everything!

  9. If the carbine version of the Scorpion EVO doesn’t have a lame fake silencer on it, CZ will make some money off me.

  10. Great write up.
    I want one of each.
    And a RONI and FAB too.
    Hey, I’m in town, let’s do some other write-ups.

  11. The Scorpion has proved itself in theater by ally forces, military’s, police, and been doing it for years. It has proved its self. Not only in semi but in 3 rnd but full auto also, when the Sig has problems in semi auto use alone (not to mention it looks like its foregrip looks as it is made out of legos). Track record for years says it all!!

  12. I’ve had the opportunity to shoot both for approximately 500 rounds each. At the end of the day, I couldn’t justify the near double price of the MPX, and ended up buying a CZ scorpion.

    It’s my first CZ and as a die hard Sigaholic, I was actually surprised in my initial decision. After shooting my own CZ scoprion, it just reaffirmed my choice. This thing is a blast! Currently outfitted with a trs25 and shockwave blade all for under $900. Hard to beat that.

  13. Love the side by side comparison. I was wondering, does the MPX-P come with a threaded barrel or was that an add-on. Thanks

  14. MPX all the way. I think the plastic CZ looks stupid. Kind of reminds me of a Hi-Point or some other type of cheap gun like that. You get what you pay for. The Sig just feels so nice and solid in your hands. Can the CZ change calibers(9mm,357sig,40s&w) in 2-3 minutes like the MPX. Bottom line is get what you like. As far as reliability issues, mine has never had any failures. You can find comments on the internet of issues with any gun. If money is what make your decision about which gun to buy then perhaps get a better job or put your gun on layaway. I personally would never own a cheaper, ugly gun just to save a few hundred bucks!!! Just my opinion, if you don’t agree keep it to yourself please.
    P.S. One of my buddies owns a hipoint 40s&w carbine. It runs like a top and is super accurate but i personally wouldnt buy one of those hideous guns either…

  15. Own the CZ and am very impressed. One hole 5-shot groups at 25 and MOA out to 50. Have 4-30 round mags and 2-20 rounders. Mag couplers are enroute to give me 60 rounds. It digested 10 different brands of 9X19mm without any issue. Topped with the Vortex Strikefire II red dot I’m well armed with this weapon. Thanks CZ for a wonderful weapon.

  16. Extar EP9 – accurate, runs like a champ and takes Glock magazines. All for under $500.00.

  17. 25 yards, one hole.
    15 yards, a series of holes that the author states is “one” hole.

    And yet you say the accuracy is a wash between the two?

    Get your eyes checked.

    Or, I don’t know, actually shoot them at the SAME distance to make it a legitimate comparison.


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