SHOT Show 2019 Highlight: SIG Sauer’s MPX Copperhead

The National Shooting Sports Foundation’s annual Shooting Hunting Outdoor Trade (SHOT) Show is one of the largest and most exciting trade shows in the firearms industry. Every year in January, thousands flock to Las Vegas to see what’s new and on the horizon for the community. From hunters to military and law enforcement, there is a vast array of participants, and attendees who are certain to find something new and interesting.

One of the new innovations that stood out to me was the SIG Sauer MPX Copperhead, the newest edition to the SIG MPX powerhouse family. The MPX was first introduced in 2013, taking the gun industry by storm. Boasting innovative firsts, it quickly became a leader in the submachine gun category.

SIG Sauer held a private range day the Sunday before SHOT Show kicked off, and I was able to spend some time with the Copperhead during this event. I had previously shot a prototype at the 2018 Athlon Outdoors Rendezvous in Montana and was eager to test the production-ready sample. The “wow” factor is in full force with this 9mm tack driver. The MPX Copperhead is a compact, lightweight, semi-automatic counterpart to the submachine gun, the latter of which is only available to military and LE.

MPX Innovation

SIG rocked the gun world when they first introduced the innovative MPX. The ability to run any type of ammunition, regardless of brand or weight, without making adjustments to the gas valve is ingenious. The MPX Copperhead is no different; the short-stroke, gas-piston operating system gives it the same function, only more compact.

“The MPX Copperhead considerably reduces the length, width and size of the MPX platform, making it the most compact addition to the MPX family of firearms,” said Tom Taylor, chief marketing officer and executive vice president of commercial sales at SIG, in a press release. “The Copperhead is the perfect combination of the features and performance our consumers expect from a SIG MPX in a compact package.”

The MPX Copperhead is 14.5 inches long and weighs in at just 4.5 pounds. The barrel is 3.5 inches, incorporating an integrated muzzle flash hider. It features a monolithic Elite Series Cerakote finish upper receiver, integrated stock knuckle lower, and is equipped with the SIG Sauer Pivoting Contour Brace (PCB). This brace features a patented swivel operation that allows the MPX to adapt to the individual shooter’s movement. This affords the shooter perfect placement and rapid deployment. Operating from a fully closed and locked rotating bolt offers above-par safety and reliability. The Copperhead is fully ambidextrous, featuring a dual-sided selector switch, magazine release, charging handle, and bolt release.

The entire concept of the Copperhead is fascinating. So many features of the MPX platform are packed into this compact version yet it retains the same power and performance.

Utilizing the pistol brace

When I shot the prototype in Montana, I utilized the PCB brace. The brace truly adapts to the shooter’s movements, making positional shooting more comfortable and accurate. At SIG’s range day, we were asked not to shoulder the Copperhead — or use the brace at all. I’m not sure as to why, and, as an invited attendee, I didn’t push the issue.  

Whether it is legally permissible to shoulder a pistol equipped with a stabilizing arm brace is a confusing topic, in part because the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) has changed its view on the subject in recent years. So, does shouldering an AR pistol turn it into a National Firearms Act (NFA)-restricted short-barreled rifle and thus require a tax stamp — or perhaps make it illegal to own in your state?

A letter released by the ATF on March 21, 2017, titled “Reversal of ATF Open Letter on the Redesign of ‘Stabilizing Braces’” says, in short, no.

Per page 3 of the reversal letter: “To the extent the January 2015 Open Letter implied or has been construed to hold that incidental, sporadic, or situational ‘use’ of an arm-brace (in its original approved configuration) equipped firearm from a firing position at or near the shoulder was sufficient to constitute a ‘redesign,’ such interpretations are incorrect and not consistent with ATF’s interpretation of the statute or the manner in which it has historically been enforced.”

However you choose to shoot it, the Copperhead is so lightweight and compact that my accuracy and follow-up shots were consistent regardless of shooting position.

One benefit, however, of shouldering the Copperhead is recoil management. A little muzzle rise is a natural result of mixing a high-velocity round with a lightweight platform, and I instantly noticed it when I shot the Copperhead. Training and time on the range as a serious shooter (i.e., running drills) will counter this and enable you to maintain accuracy while keeping the rate of fire high.

That said, with the Copperhead being snappy and having a shorter barrel, the shooter must also be conscious of hand location in proximity to the muzzle. This gun has a hand stop, but it’s important for shooters to maintain awareness in order to safely control the forend.

The Copperhead is great to run regarding firing and manipulations, but don’t let its diminutive appearance fool you — it is a force to be reckoned with.