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FN 509 Midsize Semiautomatic Pistol Tactical Upgrade: Full Review

The FN 509 Midsize semiautomatic 9mm handgun gets the “tactical” upgrade for the perfect fit—not too large, not too small.

FN 509 Midsize Semiautomatic Pistol Tactical Upgrade: Full Review

(Michael Anschuetz photo)

On May 31, 2022, at the NRA Annual Meeting & Exhibits, FN revealed the 509 Midsize Tactical alongside launches of the FN 15 DMR3 and SCAR rifles that now wear MultiCam. If you were not one of the 50,000 who attended the convention in Houston, Texas, (or visited the FN booth) the 509 Midsize Tactical may have gone unnoticed.

The 509 Midsize Tactical expanded FN’s “Tactical” lineup, which already includes the FN 509 Tactical (the full-size original) and the 509 Compact Tactical. The new 509 Midsize Tactical incorporates the slide from the full-size 509, meaning that it is also equipped with the Low-Profile Optics-Mounting System (LPOMS). The slide sits on the existing Midsize grip frame, so the handgun product manager only had to mix and match assemblies to come up with this model. Was the Midsize model’s introduction simply to keep the 509 relevant? No. I believe that FN found a noticeable balance of utility with this arrangement.

FN 509 Midsize Tactical Upgrade Middle-of-the-Road Profile
Incorporating the slide from the full-size 509 to the 509 Midsize frame means it also sports the LPOMS. The middle-of-the-road profile does it’s job. The 509 Midsize Tactical is small enough to conceal carry, but it offers great capacity, flexible utility, balanced handling and accuracy. (Michael Anschuetz photo)

“Building on the success of both the FN 509 Tactical and the FN 509 Midsize, our team combined the best features of both pistols into the FN 509 Midsize Tactical,” said Chris Cole, vice president of sales and marketing for FN America. “The 15-round grip frame with the optics-ready tactical slide assembly offers our customers another strong contender for concealed carry and personal protection in the FN 509 family.”

FN 509 Midsize Tactical Upgrade Disassembly
(Michael Anschuetz photo)

A New Category?

Enough gun companies are now doing this kind of mix-match approach that I’ve started calling such pistols “Crossovers.” Crossovers meet current carry trends for longer and shorter slide preferences, as well as capacity needs. Of course, they also fill manufacturers’ gaps between major introductions, so brands are not altogether overshadowed by a competing new product — and the 509 Midsize Tactical does have competition.

The Crossover category currently includes the Glock 45, which features a full-size G17 Gen5 model frame and the compact slide of a G19. The G45 is available with or without Glock’s Modular Optic System (MOS) system, which is why its retail pricing spans from $539 to $698.

FN 509 Midsize Tactical Upgrade Disassembly
The Midsize 509 Tactical is standard with the industry’s best optic adapter kit. Tritium iron sights co-witness, too. (Michael Anschuetz photo)

Based on the striker-fired G3 series, Taurus launched its G3X and G3XL in April 2022. The G3X features the G3 full-size grip for its larger capacity and topped it with the compact slide from the G3C. Conversely, the G3XL features the more compact, reduced-capacity frame of the G3C topped with the full-size G3 slide. These models have yet to include the Taurus Optic-Ready Option (TORO) and interchangeable backstraps/modular grips, which are reasons the G3X and G3XL enjoy the category’s lowest retail price of $342.98.

Knowing that Crossovers combine assemblies from existing products to create new models, the significance may seem superficial. However, these pistols have attracted a lot of attention. As it turns out, there is a real need. Many who conceal carry a handgun as part of their everyday lifestyle appreciate the benefits of having more than enough rounds available to fight with. Not having to reload saves precious time. On the other hand, concealing a magazine over a certain length can be impractical. An extended magazine makes perfect sense as a backup, but a stick mag poking out of a t-shirt does not.

To add, carry optics have made us rethink EDC. A slide that’s longer than it has to be is superfluous. How much sight radius is necessary if your pistol is equipped with an optic? We’ve already demonstrated that a longer barrel isn’t going to improve an optic user’s accuracy potential out to 20 yards. And if you prefer appendix carry (or need to sit a lot), a long-side pistol isn’t comfortable anyways. Crossover pistols offer a balanced feature-set and practicality.

FN 509 Midsize Tactical Upgrade Trigger Safety
The trigger integrates a safety, which is why it is hinged in the middle. Pull weights averaged between 5 and 6 pounds. (Michael Anschuetz photo)


The full-size 509 Tactical model arrived in April 2017, which launched FN’s Tactical series. This line extension added a threaded, extended barrel to the 509 and a slide milled to accept a reflex optic adapter plate. All 509 Tactical models retail for $1,069, including the new 509 Midsize Tactical. By 2018, these Tactical models were released in flat-dark earth (FDE). The latest 509 Midsize Tactical is offered in both black and FDE from the get-go.

FN introduced the 509 Midsize model ($799) in January 2019. It was followed by the 509 Midsize with Modular Red Dot (MRD) system in August 2019. In April 2020, we saw it colored in FDE for the same price. It was predictable that the 509 Midsize would be offered in FN’s Tactical configuration. What I didn’t expect was how much I was going to prefer this combination of features. It struck a chord.

The 509 Midsize Tactical includes a threaded barrel and is optic-ready. The 509 Midsize has a 4-inch barrel, while the 509 Midsize Tactical’s was extended to 4½ inches to offer suppressor-ready ½-x28 threads. When not in use, the threads are protected by a knurled endcap, too.


Though the Midsize MRD models were interesting, those who were not immediately intent on equipping the handgun with a reflex sight had to live with the large, suppressor-height sights. (The front blade looks like a shark fin and the rear is a notched brick.) Though too pronounced as standalone sights for EDC, FN was simply supporting customers who would eventually equip the 509 Midsize MRD with an optic and/or suppressor use. I get it.

FN 509 Midsize Tactical Upgrade Ambi Controls
Controls are truly ambidextrous — including the magazine release. There is a functional mag-release button on both sides. (Michael Anschuetz photo)


The LPOMS is, in my opinion, the best mounting kit available for an optic-ready pistol. Not too long before this evaluation, I attempted to mount an Ameriglo Haven red dot sight to a G19 Gen5 MOS for testing. Only after acquiring the pistol did I discover that the MOS adapter plate kit did not include the right length screws to complete the job. This was frustrating because the Haven uses the common Trijicon RMR footprint. In contrast, I’ve never struggled to mount an optic to an FN 509 with LPOMS. For this evaluation, I confirmed the flexibility of FN’s LPOMS mounting system by testing the 509 Midsize Tactical with an Ameriglo Haven ($380,, Leupold DeltaPoint Pro ($450,, Trijicon RMR Type 2 ($720, and Vortex Venom ($350,; these all worked great and did not require additional hardware. FN provides Tactical models with every adapter plate and screw type needed to secure a reflex sight to the slide. It’s the most comprehensive mounting kit provided with any optic-ready pistol.

Don’t need to configure your pistol with a red dot? Like the 509 Midsize MRD, the 509 Tactical models are also standard with suppressor-height sights. However, the rear is shrouded with the MRD coverplate, which has protective wings to guard the sight. The design is reminiscent of the type used on military rifles and machine guns. Need to make a sight adjustment? The rear sight stays in place when the MRD plate is removed, which allows the rear sight to be drift adjusted for windage. When mounting an electronic optic, the zeroed rear sight stays put and can be aligned with the front through the window. This configuration is the perfect backup system for a pistol that could see use with a red-dot sight.

FN 509 Midsize Tactical Upgrade Midsized Favored by G&A Staff
Out of the three 509 Tactical sizes currently available, G&A staff found themselves going back to the Midsize model at the range. (Michael Anschuetz photo)


In March 2022, I attended a media event highlighting FN’s new handguns. Attention was focused on the High Power, but I left impressed by the performance of the 509 Midsize Tactical. The model name suggests that it is merely a line extension, but it proved to be so much more. I shot it alongside the full-size and compact variants of the 509, and many of us kept going back to shooting the Midsize Tactical. It has modularity with the optional backstraps. It has three different grip textures, just like other 509 models. It’s truly ambidextrous, meaning that you don’t have to disassemble the magazine release and reverse its orientation to the opposite side; there is already a pronounced, easy-to-reach magazine release button available on both sides of the grip! Even the slide release/slide lock lever is mirrored.

With 15 (plus one) rounds loaded, the 2-pound weight is perfectly balanced for effective recoil management. Add a suppressor to the threaded barrel and the muzzle doesn’t seem to jump. Besides weight distribution, I credit some of this control to the grip’s complex contours and textures.

FN 509 Midsize Tactical Upgrade Magazine
One 15-round flush magazine and one 24-round extended magazine are included. Ten-round mags are optional. (Michael Anschuetz photo)

FN Understands

More evidence that FN gets us is the spare magazine. For EDC, I carry the 15-round magazine. It’s a nice reminder that the 509 Midsize Tactical accepts larger 17-rounders from the full-size 509 models, and for those living in mag-restricted jurisdictions, 10-round magazines are provided. However, included with the excellent (and convenient) nylon pistol case is a 24-round magazine. Twenty-four rounds — not counting the round most of us would carry in the chamber! The 6½-inch magazine not only delays the need to reload in a gunfight, but it carries well in a front pant pocket or pouch. Best of all, the sleeve that fills the would-be gap between the bottom of the grip and the magazine floorplate isn’t a sleeve at all; the 1.87-inch spacer is actually a one-piece floorplate that slides on from the front! It doesn’t feel cheap like others do.

Regardless of which magazine you shoot with, all 509 models reload easily. The double-stack-size hole is a huge funnel for the tapered magazines, and the bright orange followers are visual indicators that can be peripherally seen through the ejection port if the pistol goes to slide lock.

FN 509 Midsize Tactical Upgrade Suppressor
Adding a suppressor to the threaded barrel is simple and recommended! When not in use, a knurled endcap protects the threads. (Michael Anschuetz photo)

Miracles Happen

At the time of this writing, I’ve been evaluating the FN 509 Midsize Tactical 9mm for three months. It’s a toss-up whether I prefer the black or FDE version more, but both of Guns & Ammo’s test samples shot the same. No matter the brand of defensive load, you should see five-shot groups averaging between 2 and 2½ inches from a bench at 25 yards. Range ammo typically averages 3 to 4 inches unless you feed the 509 match loads. What surprised me at the range was the frequency that I could group four rounds in one hole — sometimes around a half-inch. However, as results indicate, there was always a fifth flyer that would open the group up closer to its 2-inch average. Jacob Avery as my witness (you don’t know him), on May 26, 2022, my best four-shot group from 25 yards measured .23 inch! (We took a selfie and kept the target.) It’s difficult to explain, the accuracy potential in these guns seems to tighten the more I shoot them.

We can see the progression of the 509 series, and thus, we can predict future models. The lesson I was reminded of while evaluating this new entry is not to draw conclusions too early. You must handle and experience the 509s separately for yourself. It wasn’t that long ago when the 509 first appeared in Guns & Ammo (July 2017), and there have been several iterations brought to market since. Though they share certain commonalities and performance traits, each model presents a unique set of features and handling qualities. If your preference is to carry a mid-size, optic-ready, double-stack pistol, you would be remiss if you did not consider the FN 509 Midsize Tactical.

FN 509 Midsize Tactical

  • Type: Recoil operated, semiautomatic
  • Cartridge: 9mm
  • Capacity: 10 rds. or 15 rds./24 rds.
  • Barrel: 4.5 in., threaded
  • Overall Length: 7.9 in.
  • Width: 1.35 in.
  • Height: 5.2 in.
  • Weight: 1 lb., 11.9 oz.
  • Grip: Interchangeable backstraps; molded texture
  • Finish: Black or FDE
  • Sights: Trijicon, three-dot; optic ready, mounts incl.
  • MSRP: $1,069
  • Manufacturer: FN America, 703-288-3500,
FN 509 Midsize Tactical Upgrade Chart
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