Gun Digest

FN 509 Compact: Living Up To Family Standards

From left to right, FN 509 Midsize MRD, FN 509 Compact MRD, FN Tactical.
From left to right, FN 509 Midsize MRD, FN 509 Compact MRD, FN Tactical.

The FN 509 Compact is the newest addition to the popular striker-fired pistol line, but not the least … well, in everything except size.

How The FN 509 Compact Continues To Advance The Line:

Even though FN’s pistols have traditionally been ahead of the trend, FN isn’t often one of the first brands people think of when standing at the gun counter. There’s a good reason for this: The company’s focus has largely been on building the best weapons possible for war fighters, not the civilian pistol market.

With 16 variants of the FN 509 introduced since April 2017, that’s a pretty clear sign that FN America is taking pistols very seriously.

The FN 509’s Hammer-Fired Heritage

Looking as far back as the FN FNP, which was developed for the 2006 Joint Combat Pistol Competition, you see the fully replaceable frame rails carried over to every FN pistol introduced afterward. The JCP competition also produced the FNP-45 Tactical, the first commercially available handgun to offer a factory multi-optics mounting solution.

In 2011, FN took the FNX and further evolved it into the FN FNS for the civilian and law enforcement customer who wanted a striker-fired pistol rather than a more traditional DA/SA pistol.

The last evolution of the FNS pistol was the FNS Compact, introduced in 2015. While the FNS Compact saw some limited success with legally armed consumers, it never saw wide adoption.

Competition-Forced Evolution

When the U.S. Army decided that its Beretta M9s were past their service life, the announcement of the XM17 Modular Handgun System competition made every major pistol manufacturer jump to come up with something that fit the requirements.

Despite the FN 509 Compact’s small size, this pistol shoots like a much larger gun. Also, if you didn’t know better, you might mistake the fantastic slide serrations for a high-end aftermarket milling job.

There was a common theme in the submitted pistols: Nearly all of them were an evolution of an existing design. After all, a $580 million government contract isn’t the place to debut an unproven cutting-edge pistol.

FN’s brass ordered the engineering team to drop everything and build a pistol that met the MHS requirements. Because the FNS Compact was the most evolved pistol in the FN stable, it made sense to use it as the basis for the company’s XM17 submission. After much design work, the FNS Compact was transformed into a pistol built for warriors and capable of handling high-pressure 9mm loads.

Bone Up On FN Guns:

FN’s XM17 Pistol Becomes the FN 509

Keeping true to its track record of evolving a pistol to meet the needs of civilian and law enforcement consumers, FN worked with industry experts and law enforcement end-users to refine the XM17 prototype. The result was the FN 509 Standard, launched in 2017.

Refinements made to the FN XM17 prototype were very subtle and centered on enhancement of the texture used on the pistol’s grip. In addition, FN’s engineers made some small changes so that the 509 was reliable with commercial ammunition. The 509 that landed on dealer shelves is nearly the pistol that made it to the final three in the MHS trials.

The FN 509 Standard

At the time the FN 509 was introduced to the U.S. market, every other XM17 MHS submission had been revealed—except for Glock’s. Pistol nerds like me were clamoring for more information about what FN had cooked up for MHS, and I was not disappointed in what FN brought to the table.

When reviewers got their hands on the FN 509, the feedback was nearly universally positive, although some reviewers reported that the magazine release could be tough to activate. Also, the trigger on some examples was reported to be a touch on the heavy side for use as a target pistol.

Like the XM17 pistol, the FN 509 features fully ambidextrous controls, some of the best slide serrations I’ve ever seen on a factory pistol, an outstanding cold hammer-forged barrel and a grip texture that looks a bit goofy—with four distinct textures—but performs amazingly well in all conditions.

The FN 509 Tactical

The FN 509 Tactical that was launched in July 2018 is yet another evolution that shares many of the same features that made the FN 509 Standard such a great pistol. Nevertheless, FN America’s design team added some enhancements to the Tactical in response to consumer and subject matter experts’ feedback.

There are several magazine sizes to choose from. Just make sure to use the correct over-insertion spacer to prevent ejector damage.

The Tactical brought a new slide release that’s influenced by the TangoDown Vickers slide release. It’s a huge improvement over the smaller slide release that was an obvious carryover from the FN FNS. Additionally, the issue that some reviewers reported—that the magazine was sometimes a challenge to release—was also addressed with an enlarged release button.

FN also added a 24-round magazine option with the FN 509 Tactical that’s roughly the same length as the slide. Keeping the length of the 24-round mag reasonable meant that if you could conceal the Glock 19-length slide, concealing a larger reload or carrying it on a duty belt was possible.

Lastly, the Tactical included a cold hammer-forged, 4.5-inch barrel with ½x28 threads. FN even designed a thread protector with an O-ring inside it that stops it from loosening. Also included was a reduced-power recoil spring assembly to cycle even the lowest-power target ammunition, as well as hard-to-cycle frangible ammo.

The FN Low Profile Optics Mounting System

The 509 Tactical’s gift to shooters was the truly innovative FN Low Profile Optics Mounting System.

Previously, if you wanted to mount an MRDS (such as a Trijicon RMR) to a pistol slide, there were few good options. Direct milling has been, and remains, the most robust solution, but factory options before FN’s new system have been less than ideal for one reason or another.

The number of red-dots the FN mount is capable of accommodating grows constantly as new red-dots are released. Because the system is so adaptable, accommodating a new mount style, such as the one used on the Aimpoint ACRO P-1, is as simple as making a new adapter.

FN dispensed with the need for thread-locking compound by using an O-ring sandwiched between the slide and the optic-specific MRD plate to keep the screws secure. Not only does this make installing a red-dot and changing batteries easier, it’s also nearly as robust as the best direct-mill solutions.

The Aftermarket Embraces FN’s 509

One of the largest problems that plague new pistols is that aftermarket support doesn’t materialize. Thankfully, that’s not the case with the FN 509 platform.

Holsters: Top-tier companies such as Henry Holsters, PHLster, ANR Design and Safariland offer holsters that cover just about every concealed-carry preference. I believe the Henry Holster Spark for the FN 509 with a Streamlight TLR 7 is the way to go when it’s paired with Discreet Carry Concepts’ Mod4 Universal Clips.

Triggers: Currently, only two companies are offering a trigger for the FN 509—Apex Tactical and Volker Precision. While the Apex trigger has ruled the market, the new Volker trigger has some interesting features: Where the Apex trigger uses an uncoated trigger bar and stamped sear, Volker is using a nickel-boron nitride coating on the trigger bar and bar stock-machined sear.

Comps and Barrels: There are options offered by Weapons Armament Research, Parker Mountain Machine, Henry Holster and Volker Precision. Don’t own a 509 with a threaded barrel? Apex is offering a fluted barrel that’s dimensionally identical to the FN-produced barrel. Apex even includes a reduced-power spring in case you want to install a compensator.

Magwells and Backstraps: For some reason, FN chose to leave two large strips smooth and completely devoid of texture. There are only two companies offering new backstraps that add more texture: Volker Precision and Agency Arms.

The FN 509 Midsize

Early in January 2019, FN dropped the 509 Midsize, giving it all the same features the FN 509 Standard has—but in a size most closely compared to the Glock 19. Some of the evolutionary updates were carryovers from the Tactical, while others, such as the improved trigger shoe, were brought into the mix. The new shoe now had a much flatter face to aid in ensuring the trigger is more constantly pulled straight to the rear. The Midsize saw other minor changes, such as a reshaped fence around the magazine release that makes magazine changes easier.

The Midsize uses the reduced-power recoil spring from the Tactical to make the slide easier to manipulate. FN says that during testing, there was no degradation of reliability or longevity of the recoil spring. However, this pistol can’t be fed a steady diet of +P or 9mm NATO ammunition.

More magazine options come with the FN 509 Midsize: a 10-round compliant version, a 15-round standard-capacity magazine, the FN 509 Standard’s 17-round magazine (when used with a spacer sleeve) and the 24-round (when combined with a new base plate that incorporates the over-insertion spacer into it).

MRD 509 Models Expand the 509 Line

During SHOT Show 2019, the FN 509 MRD was quietly announced as an option for law enforcement-only customers. We also saw the launch of the 509 Midsize MRD, which had all the features of the Midsize but paired with the optics-ready slide from the Tactical.

Out of all the 509 variants introduced, the Midsize MRD is my favorite because of its concealability, the included features and the fact that the pistol recoils no more than the Tactical.

The New FN 509 Compact

The whirlwind of new models brings us to the FN 509 Compact—the latest in the 509 family launched in January of 2020. FN did it right and launched a pistol other manufacturers might refer to as a “sub-compact” with the company’s new optics mount right out of the gate.

FN’s Low Profile Optics Mounting System is every bit as innovative as the plate system first used on the FNP-45 Tactical in 2006.

The new Compact features a departure from the 4-inch slide (that every other iteration of the 509 has sported) with its new, 3.7-inch barrel cut flush to the end of the slide.

The new frame size also meant new magazine options, such as the flush-fitting, 10-round mag or the 12-rounder that sports a finger extension. As with the Midsize, the Compact can use the other magazine sizes for the 509, as long as the appropriate magazine spacer is used.

This rundown of the FN 509’s history was spurred by the release of the FN 509 Compact, so it makes sense that I used the smallest pistol in the line for accuracy testing. In theory, the Compact should have the least impressive numbers.

That wasn’t the case, however. With FMJ ammunition printing five-shot groups between 0.392 and 1.1 inches at 10 yards and 1.745 and 4.499 inches at 25 yards from a hasty rest, the Compact exceeded my expectations.

The consistency I saw at 25 yards with good defensive ammunition in my example was no less impressive: Federal HST 124-grain produced a 2.020-inch five-shot group for the best out of the five ammo types tested. The worst was the Federal HST 124-grain +P with a 2.812-inch five-shot group.

Each 509 MRD pistol comes with everything you need to mount the optic of your choice. (The ACRO plate is sold separately.)

FN managed to give consumers a Glock 26-sized pistol that accepts every red-dot the Tactical will. It also made sure the Compact would accept every weapon light on the market (you do have to modify a Surefire X300 by removing the DG switch blank, but the light will fit).

What’s Next for the FN 509?

That’s a hard question to answer with certainty. There are still a few gaps in the FN 509 lineup that could be easily addressed.

Using Glock models as sizing benchmarks, the 509 line still lacks a 43x/48-sized pistol, a Glock 34-sized gun and a true Glock 17-sized gun. The next release is as much a mystery to me as it is you, but one thing’s for sure: FN will certainly apply all the evolutionary changes the model has seen since the Standard’s introduction in 2017.

I, for one, will be excited to see what the future brings (I’m hoping for a Glock 34-sized FN 509 to replace my Gen 5 Glock 34 with a pistol better suited to being a test mule for mini red-dot sights). After all, the dot is the future … and the future is now.

FN 509 Tactical
Caliber: 9mm Luger
Action Type: Double action only (striker-fired)
Controls: Ambidextrous slide stop and magazine release
Frame: Polymer w/replaceable steel slide rails
Magazine Capacity: 10- and 17-round flush fit or 24-round w/spacer
Weight Unloaded: 27.9 oz.
Barrel: 4.5 in., threaded, ½x28 cold hammer-forged stainless steel w/1:10 RH twist
Length, Width, Height: 7.9 in. L, 1.35 in. W, 5.75 in. H
Trigger Weight as Tested: 6 lb., 3 oz.
Sights and MRDS Mounting: Green tritium suppressor-height sights and FN low-profile optics mounting system
Included Accessories: 2 backstraps, 3 magazines, MRDS cover plate, zippered case, MRDS mounting kit, standard recoil spring, reduced-power recoil spring

FN 509 Midsize MRD
Caliber: 9mm Luger
Action Type: Double action only (striker-fired)
Controls: Ambidextrous slide stop and magazine release
Frame: Polymer w/replaceable steel slide rails
Magazine Capacity: 10- and 15-round flush fit or 17- and 24-round w/spacer
Weight Unloaded: 26.5 oz.
Barrel: 4 in., cold hammer-forged stainless steel w/1:10 RH twist
Length, Width, Height: 7.4 in. L, 1.35 in. W, 5.3 in. H
Trigger Weight as Tested: 5 lb., 10 oz.
Sights and MRDS Mounting: Black suppressor-height sights and FN low-profile optics mounting system
Included Accessories: 2 backstraps, 2 magazines, MRDS cover plate, zippered case, MRDS mounting kit

FN 509 Compact MRD
Caliber: 9mm Luger
Action Type: Double action only (striker-fired)
Controls: Ambidextrous slide stop and magazine release
Frame: Polymer w/replaceable steel slide rails
Magazine Capacity: 10-round flush fit; 12-round w/extension; 15- and 24-round w/spacer
Weight Unloaded: 26.5 oz.
Barrel: 3.7 in.; cold hammer-forged stainless steel w/1:10 RH twist
Length, Width, Height: 6.75 in. L, 1.35 in. W, 5.2 in. H (4.8 in. H w/optional flush fit magazine)
Trigger Weight as Tested: 5 lb., 7 oz.
Sights and MRDS Mounting: Black suppressor-height sights and FN low-profile optics mounting system
Included Accessories: 2 backstraps, 2 magazines, MRDS cover plate, zippered case, MRDS mounting kit

For more information on the FN 509 Compact, please visit

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