The “new” MP5? Author says it’s better than that! Read MORE…
The Sig MPX is an innovative configurable PDW (Personal Defense Weapon) platform that can be purchased in a variety of forms including pistol, pistol plus Sig Brace, rifle, and NFA regulated SBR. The model I choose for review is the MPX Pistol with folding Sig Brace adapter. This setup can be easily purchased just like any handgun on the market.
WHY A SIG MPX
Of the guns most lust to have, the H&K MP5 is on that list. It is the quintessential 9mm PDW that still serves in many militaries, law enforcement SWAT teams, and global hostage rescue teams for many reasons — it is utterly reliable, short, accurate, easy to shoot fast, and pretty hard hitting. We have all built up an image of perfection in our minds and all want one. Then you actually fire an MP5 and find out that the looks are still there, but the years of experience are showing.
As a civilian, you cannot buy a new MP5. Original $5000+ used MP5s are a bit beat up with a been-around-the-block-a-few-times look, sights are not as user friendly as modern day designs, mag well is not particularly easy to find during reloads, the manual of arms is so different from our ingrained AR15 habits that it feels a little weird, there is no last round hold open on most MP5s (some do), optic mounts are goofy, the stamped receiver looks cheap and outdated, replacement parts are getting super pricey, and the price the user pays (if they can find one) is still too high. In this case, pulling a factory-fresh MPX from its box delivers everything I want without the worry of the mileage and cost of an MP5.
Despite its reputation H&K has made some poor marketing decisions. H&K was in some financial deep water and why they would not do consumer retro releases of some classic guns is beyond me. At a time when $400 Euro H&K P7 trade in guns are going for $3000 on GunBroker.com and shooters are still screaming for a civilian MP5 it seems H&K is leaving money on the table. Why has the semi-auto SP6K (updated MP5 semi-auto pistol) not made it to U.S. shores? Sig Sauer decided there was money to be made in the MP5 market and developed the MPX to go right after the throat of H&K with a supportable, adaptable, highly configurable 9mm PDW format. Instead of “me too” product, Sig also addressed all those gripes users had with the MP5 design. If you have always wanted an MP5, the Sig MPX will deliver more grins per dollar and I would argue is far better!
SIG SAUER MPX
The MPX is arguably the sexiest and most titillating thing in decades to come out of Sig Sauer since the MCX was introduced with the same profile but in 5.56 NATO. I mean good lord look at this thing — it is dripping with custom design concepts.
The design perfectly mimics the AR controls; however, Sig did not stop there and added full ambi-controls on the magazine release, bolt charging handle, bolt release, and selector switch. Everything you can do with your support hand, is possible with the shooting hand. Ambi selectors always annoyingly rub on my trigger finger, however Sig has made the right side selector toggle as short as possible to minimize this known AR15 ambi-selector issue. The charging handle stroke is a bit shorter than your AR15. All around all the controls are well executed.
Sig made the MPX easy to customize. The new G2 version is fully KeyMod-compatible with the plethora of aftermarket keymod accessories. The picatinny spec rail at the rear can be left bare, or with just one torx screw a folding or fixed adapter can be used to mount a AR15 compatible cheek stabilizing tube and/or Sig Pistol Brace. If you have received your Form 1 NFA Tax stamp, one of Sig’s fixed, folding or or collapsible stocks can be added. Even the grip and trigger group are AR15 compatible. Flexibility is the base of this design.
The MPX is also a caliber-convertible platform which offers users the option to swap out barrels and bolt systems from the factory 9mm to .357SIG or .40 S&W all just by removing two bolts.
The heavily flared magazine well makes authoritative insertions fast and easy. Honestly, the MPX is hard to shoot without cracking a giant smile.
Even the magazines are freaking awesome looking. Lancer Systems who is well known for premium magazines developed the design for the MPX. Mag functioning is smooth and flawless. Restocking rounds is push-in AR-style versus slide-in handgun mag style which lessens thumb pain.
YES THAT IS IT
Make sure you go ahead and get extra mags! I now have six. Also just plan on buying 9mm ammo in 1000 round bulk packs, because otherwise if you only take 50-100 rounds to that first range session you will feel like your hot new girlfriend/boyfriend got you worked up and then left you high and dry.
Shooting the MPX really does not feel any different than shooting any other AR15 pistol or registered SBR other than the recoil is almost non-existent. Although a completely unfair comparison, by contrast my 9mm Keltec Sub2000 has a sharp little snap but the MPX does not. Sig did a great job with the piston-driven gas system to deliver a cleaner running gun and strip out that jarring snap of the 9mm round hotly exiting the longer barrel.
Accuracy is superb. Where the MP5 would really shine were head shots under 75 yards, the MPX shines at this range as well. Hitting my Action Target hostage swinger (6-in.) at 100 yards was pretty easy also, however I did notice the 9mm round did not have the power to swing the hostage target to the other side at that range. The gun is easily a single-ragged-hole gun at 25-yards, and at 50-yards 3-4 inches for offhand groups was not difficult with quality defense ammo.
This is a superb home and personal defense gun. With the Hi-Lux Micro B-Dot red dot sight added this was a fast little gun that delivered everything I love about .223 AR15 pistols without the deafening report. The MPX has a softer handgun report out of the 8-in. barrel, far from the ear splitting boom an AR15 pistol delivers indoors and outdoors. With the right low penetration ammo such as Federal Guard Dog or the very hot Liberty Civil Defense 2000-FPS 450-FPE, the MPX delivers accurate high-energy dumping rounds combined with limited liability from pass through rounds. For me, this gun is starting to make more sense for home and backpack carry personal defense than my AR15 pistols…
The painful price point allows one to be critical of annoyances. The MPX is expensive. I understand there was a ton of R&D on this gun, however that does not lessen the entry pain when it comes time pay. Current MSRP is $2162.00.
The magwell is easy to find, as said, but tactical reloads where the bolt is not locked back require a very firm whack to get a full magazine to seat. Although technically a piston-driven gas system, and cleaner running than straight blowback operation, this is still one dirty gun after a few hundred rounds. There really is no way around it — handgun rounds equal dirty guns.
For the price, I would have expected a Tritium insert on the front sight post and two included magazines. The polymer dust cover and finger stop booth feel like they will break and any moment, but have not. The dust cover needs to be a bit beefier and I suspect one hard whack in a door jam and it’s a goner.
The magazines themselves are selling for $60-$70 each which is painful even though they are stunningly well-made. The trigger is horrible. I am stunned Sig Sauer could make something this terrible. How can Sig give me one of the smoothest double-action pistols on the market but includes a trigger that feels like it had sand dumped into it. I am glad the trigger is compatible with AR15 replacements because it is possibly the worst feeling AR-style trigger ever.
The instructions were terrible. The ten pages of obvious safety warnings should have been used to tell how to configure everything that came in the box: the extra QD slung mount took a good hour to understand how and where to attach it..
Until you break in the folding stabilizing brace, which takes about forty or fifty repetitions of feeling like you are going to snap the stabilizing brace off, you could swear that it locks both open and closed. I also found the stabilizing brace length to be about an inch too long to stabilize against the cheek. Some might find it perfect though.
The MPX had zero functional issues wasting away an afternoon and 1000 rounds of whatever was the cheapest 9mm ammo available in bulk.
This little pistol can slip into most small packs or messenger bags and delivers a very fast response option with crisp precision. I would recommend buying 20-round magazines for this carry option as the 30-rounders are a bit long. The MPX system screams for SBR stamping and that cool Sig collapsible stock. The MPX was designed for the person wanting a gateway to SBR registration — once you have your SBR Stamp, a stock swap is only one bolt away. Buy the MPX like any other pistol, go and shoot it, send in the Form 1 NFA eForm to “SBR” the gun with a gun stock, and you can still go shoot the gun while you wait for that process to complete.
The Sig MPX is well thought out, totally flexible and configurable for future upgrades. This is an investment firearm which is more than just a fun gun.
[Major Pandemic is an editor at large who loves everything about shooting, hunting, the outdoors, and all those lifesaving little survival related products. His goal is simple, tell a good story in the form of a truthful review all while having fun. He contributes content to a wide variety of print and digital magazines and newsletters for companies and manufacturers throughout the industry with content exposure to over 2M readers monthly. Click HERE to learn more.]