Picture of a copperhead snake

SIG MPX Copperhead [Hands-on Review]

We may earn a commission when you purchase through the links on our site. Find out more here.

This is the carbine for you if you like the aesthetics of the original MP5 but prefer the controls of an AR-15. Are you handy with an AR-15? Then you’ll have no issue converting your skills to the SIG Copperhead as I did. Just as its venomous namesake, this is a nimble yet dangerous beast.

SIG designed the MPX to provide an upgraded option for outdated submachine guns. Having a weapon like a Copperhead that you can carry discretely is a good idea. The Copperhead is jam-packed with cool and practical features. If you’re looking for the best 9mm carbine, consider this one. 

  • Equipped with Pivoting Contour Brace (PCB)
  • MIL-STD 1913 rail for attachments
  • Solid metal construction
  • Sleek compact design
  • Reliable and rugged
  • Less felt recoil
  • Unconventional design
  • Ambidextrous controls are the same with an AR-15
  • Small charging handle
  • Expensive

BONUS OFFER: Get your free shooting range targets to print at home!

Get your free targets to print at home!

Subscribe to our newsletter and get gun deals, educational content, hand's on reviews and news on law changes!

A Quick History

The SIG MPX Copperhead was one of the newest innovations that stood out during the 2013 SHOT Show in Las Vegas. The MPX was first introduced that year and became a hit in the firearms industry. It soon rose to the top of the submachine gun category because of its creative features. As a result, the MPX Copperhead has already landed a slew of government contracts.

Like other SIG Sauer guns, SIG Sauer developed the Copperhead in response to a specific user’s request. It’s the smallest possible backpack firearm currently available. It is also one of the most recent pistol caliber carbines (PCC) to hit the market.

SIG MPX Copperhead - Firing a SIG MPX Weapon
Firing a SIG MPX Weapon

While the SIG MPX Copperhead is on the more expensive side, there is a reason for it. The gun’s primary function is to serve as a powerful MPX platform. The goal is to maintain the same degree of efficiency and performance as its predecessor. In other words, the Copperhead is a carbine that uses a 9mm cartridge that is both compact and powerful. 

The Market for the Gun

When considering the MPX weapon from a military standpoint, some claim that pistol-caliber weapons are no longer a viable option. The introduction of the personal defense weapon (PDW) class appears to be the turning point for the submachine gun. Civilians looking for a step up from a basic pistol would likely be a fan of the MPX Copperhead carbine. 

The MPX Copperhead is also a good choice for a civilian concerned with self-protection. Its reliability, big magazine capacity, and outstanding maneuverability are all factors. The structure is compact and concealable. As a result, you can carry this pistol in a backpack or store it in your glove compartment even. The Copperhead is one of the most civilian-friendly versions of a military-grade weapon you can get these days.

SIG MPX Copperhead - Official Photo
SIG MPX Copperhead; Photo SIG Sauer official site

SIG Sauer ― The Manufacturer

SIG Sauer is a prominent manufacturer and supplier of firearms, ammunition, optics, and more. The company has a solid reputation for providing reliable pistols to law enforcement. SIG Sauer is also popular among gun enthusiasts all over the world. It is a European firm, but a well-known gun manufacturer in the US as well.

If you’re wondering why SIG is so much more expensive than Glock. It’s because Glock is meant to be a low-cost manufacturer. Some Glock 17 parts, for example, are made of polymer, which is a cheap material. Meanwhile, SIGcrafts firearms are almost entirely made of metal and alloys. The extra attention to detail costs way more. Those who desire a SIG have demonstrated that they are willing to pay a premium for a SIG weapon. 

As a result, it’s more than a branding issue. When you buy SIG, you can feel confident that you’re paying for high-quality firearms. Their weapons are flawless and accurate. In short, the expense of a SIG pistol is worth it.

The SIG MPX Series

SIG Sauer’s expertise is focused on the SIG MPX Series. The construction of this type is modular. There are machine pistols, carbines, and submachine weapons to choose from. Operational safety and reliability are substantially increased thanks to the revolving bolt and pistol mechanism.

The SIG MPX has three selective fire configurations. It comes with the standard variant or the MPX, MPX-K (compact version), and MPX-SD (suppressed model). It also has semi-automatic only versions. The MPX-P (pistol variant), MPX-PSB (machine pistol), and MPX Carbine or (assault carbine version). All are chambered in 9mm caliber. Each mark has a different weight as well as different dimensions and stock types.

SIG Copperhead Specs

ModelSIG MPX Copperhead
TypeSubmachine gun
Mag TypeMPX
Barrel Length3.5 inches (89 mm)
Overall Length14.5 inches [368 mm]
Height8 inches [203 mm]
Weight Unloaded4.5 pounds (2 kg)
Twist Rate1:10
Receiver FinishCerakote
Accessory RailM1913
Magazine Capacity20+1 detachable box magazine
ActionSemi-auto piston-operated
Operating SystemGas Piston

Look and Feel

SIG MPX Copperhead - Hands-on Look and Feel

This is an aesthetically pleasing gun that is designed to be small enough to wear on or off the body. The black pistol grip is overwhelmed by the Cerakote coating on the receivers. Nonetheless, the combination is ideal and the weapon is attractive.

The SIG MPX Copperhead is a compact 9mm handgun with a built-in folding pistol brace. It’s built on SIG’s widely known MPX PCC, which includes a short-stroke gas piston. Although the barrel is only 3.5 inches long, the ergonomics allowed it to hit steel at 50 yards with ease.

You can brace the gun against your shoulder. You could also extend your arms and operate it with a thumbs-forward hold if you want to be more precise. As a result, it’s far more adaptable than a longer barrelled PCC.

Now for Some Photos

The SIG MPX not only is fun to shoot but is also easy to carry, thanks to its ultracompact and lightweight design.

SIG MPX Copperhead - Integrated Flash Hider
(Integrated flash hider: Photo credit: Rainier Arms)

At the muzzle’s end, there’s a flash suppressor. The built-in flash hider on the Copperhead protects the crown of the barrel. It also keeps the overall length modest.

SIG MPX Copperhead - 3.5'' barrel
(3.5’’ barrel: Photo credit: Rainier Arms)

A 3.5-inch barrel is standard on the Copperhead. This weapon is only .4 inch longer than the SIG Sauer P365 compact pistol. Moreover, a MIL-STD 1913 rail runs along the top of the hefty upper receiver. This simplifies the installation of optics, iron sights, and other attachments.

SIG MPX Copperhead - Ambidextrous controls left
(Ambidextrous controls left: Photo credit: Rainier Arms

The controls are comparable to those on an AR-15: they’re well-placed and simple to use. But there are a couple of enhancements. A full-length lever on the side and a shorter lever on the right make up an ambidextrous safety. The ambidextrous safety is incredibly simple to release and re-engage.

SIG MPX Copperhead - Ambidextrous controls right
(Ambidextrous controls right: Photo credit: Rainier Arms)

On the right side of the receiver is a bolt release lever. This lever can only be used to release the bolt similar to an AR-15. It cannot be used to lock it back in place. The trigger pull is a little heavy, but it’s manageable.

SIG MPX Copperhead - PCB brace
(PCB brace: Photo credit: Rainier Arms)

The brace rotates when completely extended. Thus, allowing users to curve with the pistol itself. The PCB enables the user to focus on the sights and move around to get a better target. This also allows you to fire from your arm or shoulder brace. It can also be fitted with stocks from the SIG Sauer MPX series.

SIG MPX Copperhead - Charging handle
(Charging handle: Photo credit: Rainier Arms)

The magazine releases and the charging handle are also ambidextrous. The charging handle seemed a little stiff. But the rounds fed easily and chambered nicely. The Copperhead withdrew and expelled with ease with very little recoil.

SIG MPX Copperhead - Pistol grip and magazine
(Pistol grip and magazine: Photo credit: Rainier Arms)

The gun’s magazine well is beveled for easy insertion of the 20-round magazine. It can also hold 30 rounds, but then it gets a bit bulky. The reduced magazine has definitely helped make the rifle more concealable. Also, the pistol grip is designed to be small and comfortable while still providing a good grip.

BONUS OFFER: Get your free shooting range targets to print at home!

Get your free targets to print at home!

Subscribe to our newsletter and get gun deals, educational content, hand's on reviews and news on law changes!


The SIG MPX Copperhead is a fantastic firearm, thus it’s critical to look after it. Cleaning and lubrication are necessary. This is essential, especially if you are a frequent shooter. If your rifle has been stored for a long period, it is also vital to disinfect and inspect it. If you’re not sure where to start, Amazon provides nice cleaning kits for under $34. In the video below, youll see a demponstration of the cleaning technique and disassembly.


The SIG MPX copperhead isn’t the best weapon if you are a big accessories fan. It’s not a gun that requires many add-ons, but it’s still possible. The upper is monolithic with a Picatinny rail so that you can add your accessories with ease. However, in my viewpoint, this is a pistol that you should keep as simple as possible. Just add a nice optic, such as a Trijicon MRO or SIG Romeo 5, and you’ll be good to go.

The SIG Romeo 5 has motion activated illumination (MOTAC) and can be mounted on any platform. The Trijicon MRO (miniature rifle optic), is specially made for carbines and pistols. It provides great lens clarity to the user. It is also a useful optic for fast target acquisition.

You can’t exchange the handguard, suppressor, or muzzle device in the Copperhead. In fact, there isn’t much you can do customizing it at all. But, it is not necessary either. And after all, that’s why you’re buying this pistol in the first place, right? It boasts a one-of-a-kind design. It is not only attractive, but it is also a reliable firearm.

Shooting the Gun

SIG MPX Copperhead - Shooting the Gun
No photos allowed at my range, so an action shot from Coffee Or Die)

The trigger on the Copperhead is likewise exceptional. It’s a bit hefty, but it’s also quite short. It fires bullets with a forward pitch that keeps the projectile away from the user’s face. The ejection is consistent.

You can expand your range far more than that of a typical handgun. I made it all the way out to 50 yards and was still making regular headshots. I expanded the distance to 100 yards after assembling my targets. At this range, all loads would still hit the target. I tested the SIG Sauer’s Copperhead in a variety of tactics and proved to be simple to use and rapid to fire. In terms of accuracy, it’s an accurate compact gun. It’ll astound you how far a 9mm round can fly.


Even with a 3.5-inch barrel, the 115-grain 9mm gives me an excellent velocity. The best part is that a 9mm gas pistol doesn’t require much in the way of assistance. The piston rotating bolt reduces recoil greatly, so recoil is almost a fun little nudge. I found that recoil and muzzle rise are both low. You can have a lot of fun with this gun, and it’s quite comfortable to use.


On the market, the SIG MPX Copperhead is comparable to the CZ Scorpion Micro. Both are well-known submachine guns with similar practical uses. The Scorpion is a true PDW that is light and easy to carry and compact just as the Copperhead is. Because of its compact size, the Scorpion appears to be small, but the truth is, this gun is extensive. The SIG MPX Copperhead weighs 4.5 pounds, whereas the CZ Scorpion Micro weighs as much as 5.3 pounds.

SIG MPX Copperhead Competition - CZ Scorpion Micro
CZ Scorpion Micro; Photo credit: Moto4Moto4

When it comes to features, the Scorpion’s trigger is heavy and unpleasant to use. Meanwhile, Copperhead has a good AR-15-style trigger. The Copperhead shoots smoother and recoil is limited. It’s due to the piston and revolving bolt. Whereas, the CZ Scorpion has a large bolt, which means there is plenty of felt recoil.

For home defense, I’d go with SIG MPX because it’s simply more effective. With less recoil impulse and a better trigger, you can fire a SIG MPX easier than a CZ Scorpion.

Yet, the Scorpion is more affordable than the Copperhead. When comparing the Copperhead to the Scorpion, the difference in price is several hundred dollars. That’s a great deal of money. But if you want the smallest rifle you can fit in your backpack, the Copperhead is well worth it. Both of these pistols provide a similar quality for the price. The SIG MPX Copperhead will set you back a lot more money, but you’ll receive an all-metal weapon with more sophisticated features. The CZ Scorpion does everything the SIG does, just not quite as good. However, it is substantially less expensive.

The Final Word

The Copperhead is a fantastic compact gun that will surprise anyone who gets a chance to use it. The Copperhead is easy to operate and shoot accurately. You can customize it to fit your needs, but it’s ready to go straight out of the box. 

In many respects, this weapon is one-of-a-kind. The gun is available in a variety of configurations, the 4.-inch K version, the ultracompact model, and the pistol and rifle variant. The MPX Copperhead appears to be a well-designed weapon. With its sleek yet basic shape and distinctive Cerakote finish, it’s a true head-turner. 

The Copperhead demonstrates that it is more than competent. This weapon is a delight to shoot and, if you’re searching for the smallest 9mm carbine the SIG Copperhead might be the right choice for you. The price tag makes it a bit of an investment, but I believe it’s well-priced for what you get. It’d be useful in a crisis, and it’s also fun to shoot at the range.

What are your thoughts about this gun? Let me know in the comment section below.

You might also like these carbines articles:

Leave a Reply

Your email address will not be published. Required fields are marked *

Related Posts
N82 Tactical Holsters
Read More

[Review] N82 Tactical Holsters

In this Article: The CompanyThe OT2The OT2 MicroThe OriginalThe ProfessionalThe TuckableSo, To Sum Up What, you say…more holsters? Yessiree. With the plethora of carry guns we have today, we really can’t have too many holsters, can we? (Especially those that ride on the western hemisphere of my body, unlike all you right-handed eastern hemisphere shooters!) ... Read more
Glock 20
Read More

[Review] Glock 20: Best 10mm Out There?

In this Article: The Chevrolet ImpalaGenera(tiona)lly SpeakingA Love/H*** Thing?The U.S. ConnectionThe GunIf I Could Change One Thing…You’ve Seen One, You’ve Seen Them All…Shooting The Glock 20The Feed Ramp IssueReliability Is KingWhat Comes In The Box?Conclusions If you’ve read many of my articles, you’ll know that I frequent a very good friend’s gun shop. My buddy ... Read more
Heritage Barkeep
Read More

[Exclusive Review] Heritage Barkeep .22 Revolver

In this Article: Quick History of the Heritage Barkeep .22 RevolverWhy Do I Need an Inexpensive .22 Revolver?The New Kid on the BlockHeritage Barkeep .22 Revolver SpecsPhoto GalleryGoing OutdoorsShooting the Heritage Barkeep .22 RevolverHits and MissesRough Rider DifferenceMaintenanceAccessoriesConclusion Are you looking for an inexpensive .22 revolver to carry with you on your rambles into the ... Read more

Talk to me

Hi! I'm Mike, one of the oldest writer of Sniper Country! If you have any feedback or question about my articles, please submit it here, it's always appreciated!

[contact-form-7 404 "Not Found"]

Claim your targets for free (worth $99)!

Join 212,000 avid gun enthusiasts and claim your print-at-home shooting drills. Receive exclusive gun deals once a week and all our great reviews right in your inbox.