Category: All About Guns

   I had absolutely no shame at all & clipped it from “The American Rifleman”

How do I even begin this article? On the one hand, a straight-up history of various folding firearms would be a place to start, given that “FDP” stands for Folding Defensive Platform.

We could start with some of the flintlock and percussion-cap pistols of the 18th and 19th centuries that had folding triggers. There’s the Burgess folding shotgun of the late 1800s (a design we’re seeing coming back around in the Pak 12 introduced at SHOT Show 2026). There’s also the Russian PP-90 or the Ares FMG, and even more recently, the KelTec SUB2000, folding Glock G19 and Smith & Wesson FPC. Guns that fold are really not all that novel or new.

What about discreet firearms? There’s the Heckler & Koch MP5K Operational Briefcase or the Military Armament Corporation MAC 10 and 11 briefcase designs. The Lifecard looks like an oversize credit card until it is folded out to a single-shot pistol.

We could even toss the belt-buckle-riding North American Arms mini-revolver in the mix if we use the “hiding in plain sight” method of (non)concealment. These options are fewer and farther between than straight-up folding guns simply because of Any Other Weapon (AOW) considerations; basically, if a firearm doesn’t look like a firearm when it is capable of firing, it is considered an AOW and therefore falls under NFA regulations.

Even some wallet-style pocket holsters can run afoul of this burdensome regulation if they allow the holstered gun to fire when in the holster itself (in addition to not being exactly safe for carry).

In its folded configuration, the FDP certainly doesn’t look like a traditional firearm • Even in the open position, the FDP has an unconventional profile • The trigger also folds as part of the mechanism, and it includes an automatic firing-pin safety • The position of the extractor serves as a loaded-chamber indicator • Its unconventional appearance extends to the muzzle due to the polymer enclosure • Standard 17-round Glock magazines will fit flush in the grip, while the included 21-round magazines are slightly extended.

It’s the rare confluence of folding design and discreet nature that make the FDP so interesting. Looking at the folded firearm, it looks like—well, it looks like a tool kit you’d see on “Star Trek” or something. It doesn’t look like a firearm, which was the original intention behind the predecessor to the FDP, the FMG-9.

Drake Clark, Magpul’s sales and business development manager, walked the floor of SHOT Show with a folded FMG-9 stuck in his back pocket (with the carry handle removed), taking time to show it to folks he knew who would be interested (which should be everyone, because it’s just that darn cool).

Per Clark, as a matter of fact, “Really what we wanted was the Russian folding gun, the PP-90, but that wasn’t happening. You can’t easily get your hands on an Ares folding gun like in Robocop [2] either. If we can’t get the cool thing we want, we build it. We like cool s**t and we like tinkering, key ingredients of the Magpul recipe.”

The funny part, though, is that the FMG-9 wasn’t even Magpul’s first foray into firearm prototyping. Two years before the FMG-9 caused a stir at SHOT Show, Magpul had unveiled the PDR, a futuristic bullpup that looked like the love child of a PS90 and an M4. Around the same time as the FMG-9, the Masada—the rifle that would turn into the Bushmaster/Remington ACR— was also revealed, aiming at the piston-driven market dominated by FN’s SCAR and LWRCI’s M6. Magpul reiterated with the FMG-9 that, while not a firearm company, it could certainly produce cool prototypes.

As mentioned, the FDP started life as the FMG-9, introduced at SHOT Show 2008—yes, that’s right, if it were a human, it would be old enough to vote now. In 2021, the project transmogrified into the FDP, which is finally hitting store shelves some 18 years after the first prototype wowed us. It’s been a long road, but the Magpul (and Zev) folding pistol-caliber carbine has finally moved past the cryptid-like status of other firearms like the revitalized Bren Ten or the resurrected AutoMag.

But, it hasn’t really been in production purgatory for 18 years, mind you. When the FMG-9 was displayed at SHOT, it was fully intended to be a “look what we can do” sort of thing, not a “we are going to have this for sale.”

After returning from a vacation abroad in late 2007, Mike Mayberry (the designer behind the PMag) took inspiration from the Ares FMG, sat down at his design table and whipped up what would become the FMG-9. Some late-night hustling with an early 3-D printer, and prototypes were ready for SHOT Show in January 2008.

Controls are centrally located—as expected—on the left side of the FDP, with the magazine release, thumb safety and slide release all accessible from a firing grip • Two 21-round Magpul PMags are included with the FDP.

Having the FMG-9’s likeness displayed in an extremely popular video game series in 2011 only intensified the mystique of Magpul’s folding carbine—but remember, it was never intended to go into production.

Think of it like the fantastic concept cars that GM and Ford roll out to drum up interest, but are never going to make, like the Cadillac Sixteen revealed in the early 2000s with four-wheel steering and a 13.6 liter, V16 engine. The Sixteen was never produced, but the four-wheel steering made it into production vehicles.

What jump-started the project and turned the corner into reality was a partnership with Zev Technologies in the late 20-teens. Zev’s OZ9 pistol and its chassis concept became the basis for the FDP, the successor to the FMG. Magpul would make the polymer bits, the stock, mags and carry handle/sight array; Zev would make the barrel, slide and fire-control assembly. In 2021, the FMG-9 morphed into the semi-automatic FDP, and the folding firearm project was officially underway.

Yes, it took a little bit of time for the concept to become a reality. Zev Technologies president Taylor Goode explained, “Inno-vation doesn’t happen overnight. The FDP is literally a gun that folds.

Not a chassis—a true folding gun. Getting it from concept to production took a lot of engineering, both on the “go-bang” internals and the folding shell from our friends at Magpul. We know folks waited a long time to see this one come to life, but we set out to create an entirely new platform that exceeds expectations, not a novelty. That requires a lot of due diligence. The result has been worth the wait.”

Opening the FDP involves holding it with the hinge pointed downward, depressing the charging handle slightly and letting gravity unfold it into position. Ensure the stock cover and grip levers are locked.

So, with all this information about the work that went into the design and eventual production of the FDP, what does it boil down to? It might be tempting to dismiss the FDP as a gimmick; after all, the party trick of the unfolding is pretty showy and attention-getting.

To be fair, that’s not a bad thing; as Tamara Keel has made the case—repeatedly—in her “From the Counter” column in this very publication, that shooting is and should be fun. Bring the FDP to the range, and I guarantee you will raise the interest of your fellow shooters. It is most decidedly different; no question about that.

More importantly, it is not a one-trick pony. It offers a lot more than just the novelty of “hey, this toolkit-looking thing turns into a pistol-caliber carbine”—it’s actually a quality, capable firearm as well. Granted, when you see the names “Zev Technologies” and “Magpul” as the two companies behind the FDP, it’s tipping your hand as to how the gun can be expected to work. Neither company is any slouch in the excellence department; combined, the result should be spectacular.

And the FDP really is great. While recording some video for social media, we ran a number of magazines through the FDP quickly (slow-fire, when recorded in slow-motion, is about as much fun to watch as paint drying). Not only were there no malfunctions, but the accuracy (even with the … ahem … rudimentary sights) was top-notch. At 25 yards, I think maybe a half-dozen rounds left the C-zone of a standard IPSC target—and I was not taking my time with a solid shooting stance and focusing on the basics.

The folding component is definitely more than just an attention-getting device, too. The careful, clever engineering that goes into the FDP allows it to look rather innocuous—if you were to transport it in a messenger bag, should someone peek inside, they’d see a nondescript black case. It’s not like a large-format pistol that will immediately alert others to the presence of a firearm. Also, it takes standard Glock magazines, so if you carry a Glock-based 9 mm handgun, you’ve got the added convenience of double-dipping in your feeding devices.

Taking down the FDP for cleaning follows the same procedure as most striker-fired handguns, with the added step of removing the top cover first • Integral to the carry handle are the black front and rear sights • The folding trigger guard and molded hand stop are visible underneath the FDP • The lever on the top of the stock and on the back of the grip need to be depressed to close the FDP.

There are some drawbacks, to be sure. If you, like me, prefer red-dot sights on your defensive carbine, while it’s certainly easy enough to add one to the FDP, you lose the element of surprise. It will still fold, of course; however, when it is in the folded configuration, the red-dot sight will be clearly visible, thereby diminishing the “hiding in plain sight” aspect of the folded FDP. It’s also an SBR, which in and of itself isn’t a huge issue with the tax reduced to zero thanks to the efforts of your NRA.

However, there are certain rules currently in place with SBRs that make ownership less convenient than for suppressors—namely the requirement to alert ATF if you’re taking it to a different state. Efforts are underway to change this, but at present, it remains a consideration.

If you want to accessorize the FDP, it’s not as easy as a traditional carbine. There aren’t any M-Lok slots to add lights or lasers. There’s no section for accessories, nor any ARCA rail or sling swivel studs for a bipod mount. But again, that’s not why you’re buying the FDP. It’s the “foldy-boi” aspect, not the ability to trick it out, that gives the FDP its appeal.

Let’s talk about the folding part. It’s both ingenious and simple. To unfold the FDP, simply grasp the carry handle with the fold facing the ground. Depress the charging handle slightly, and the gun unfolds into its usable form.

Make sure that both the pistol grip and the cover plate at the top of the buttstock are locked into position, then insert a loaded magazine and use the charging handle to load. To fold it up, make sure it’s unloaded (check twice, just to be safe) and close the slide. Push the lever on top of the stock cover plate as well as the lever on the grip to unlatch both, and then the FDP can be closed.

Operationally, it’s basically an overgrown handgun. The magazine inserts in the grip, the barrel tilts up during firing (which makes it look odd when shooting with a suppressor attached, but I digress) and the controls are where you would expect them to be on pretty much any polymer-frame, striker-fired handgun.

The magazine catch is reversible, and the charging handle (which, of course, also folds) is mirrored on the right and left sides; the safety lever is right-hand only, as is the slide-release lever. There’s a vestigial loaded-chamber indicator built into the extractor that is flush with the slide when a round is inserted for additional peace of mind, too.

Since it uses a short-recoil-operated, locked-breech system rather than simple blowback, recoil is quite light, even for an already-gentle 9 mm SBR. The sights are functional and adjustable, and accuracy is about what you’d expect from such platforms.

You’re not going to win bullseye competitions with the FDP, but it’s certainly accurate enough for home- and self-defense scenarios, even those at more extended distances. At close ranges, the type you’d see for typical self-defense engagements, it’s easy to put rounds right where you want them pretty much as quickly as you can pull the trigger.

More critical is reliability—I wanted to give the FDP a workout, so more than 500 rounds were fired (It’s also crazy fun on the range, so I might have run a few more magazines than usual).

One single stovepipe was experienced, toward the end of testing when the FDP had gotten both rather hot and pretty dirty. I’m not terribly concerned, as it happened with a magazine of questionable vintage (a “pre-ban” Glock 33-round magazine I’ve owned for almost 30 years). One lone failure out of 500 rounds isn’t a dealbreaker in my opinion, especially if you clean and lubricate properly.

It’s hard not to love the FDP. Combining “cool factor” with a gun that actually functions well and can be used for defensive purposes is a fait accompli; there’s definitely cachet to having an eye-catching firearm that also serves a useful purpose.

Even if the FDP wasn’t great for self-defense—and it is great for self-defense—it would still be an important addition to the firearm market; the engineering that goes into the folding characteristics will almost certainly be carried over into future projects.

Useful, cool and reliable? That’s a trifecta of awesome in my book. If you want it because it’s neat, it certainly is. But, if you want it because it’s neat and you can actually use it, that’s its true beauty, because it simply works and works well.