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FN 509 Tactical - An Optics-Ready 9mm Pistol

The FN 509 Tactical 9mm pistol was made for the military and now it's available to us.

FN 509 Tactical - An Optics-Ready 9mm Pistol
The FN 509 Tactical was Spec'd for Uncle Sam. Now it's made for us.

Evolution happens fast in the gun industry. Take for instance the speed of development of the FN 509. In little over three years, the gun has transitioned from its origins in the U.S. Military's Modular Handgun System (MHS) solicitation, to a market-entry gun in 2017, to the new FN 509 Tactical.


On opening the soft gun case, besides seeing the flat-dark-earth (FDE) colored pistol, you're greeted by two 24-­round magazines. Think for a moment, two magazines will hold almost an entire 50-round box of 9mm ammunition — 48 to be exact (plus one in the chamber)! If you think it's too heavy to carry, you can always fall back on the 17-­round mag. If carried together, that's 65+1 rounds of 9mm firepower. Wow!

FN includes an extra recoil spring with several coils that are painted yellow for low-powered ammunition like fragible or lower-powered target loads. The silver-colored, factory-installed, recoil spring is optimized for duty, self-defense, standard-velocity ammo and low-velocity ammunition commonly used to make suppressors more effective.
The crowned barrel is threaded ½-inch by 28, making it suppressor ready. Two recoil springs are included to ensure all types of configurations will function with all varieties of 9mm ammunition.

As part of the MHS competition, all contenders were required to use suppressors. The new 509 Tactical meets that requirement with a cold-hammer-forged barrel threaded ½ inch by 28 and with an O-ring to prevent thread cap loosening.

Game Changer
Adapting a mini red dot sight to the 509 Tactical is quick and easy. Remove the factory installed slide plate and insert by unscrewing two Torx screws. Install the selected red dot on top of the slide using the appropriate combination of adapter plate, insert and screws referenced in the owner's manual. Besides the red dot sight, everything is provided. FN recommends against adding threadlocker to the screws.

What really makes the 509 Tactical a game-changer is its ability to accommodate more than 10 commercially available mini red dots (MRDs). FN accomplishes this feat through its one-of-a-kind, Low-Profile Optics Mounting System.

The mounting system fits into a cut in the slide that allows mounting an MRD lower than you could on most other pistols. Each gun comes with a bag of adapters and a chart in the owner's manual describing which MRD plate, insert and screw set to use to attach either the slide cap or red dot sight. The only thing we see they can improve upon is to mark the parts to match what's in the chart.

G&A tested two FN 509 Tactical samples with three MRD sights — a Burris FastFire 3 ($287), a Leupold DeltaPoint Pro ($520) and a Trijicon RMR ($700) — all performed well. Regardless of the MRD selected, we found the tall Trijicon suppressor-height, three-dot night sights never have to be removed and work well in tandem, co-witnessing with each red dot.

Need to adjust the rear sight? Remove two screws that secure the slide cap with a T-­10 Torx wrench for access. It's not necessary to have the slide cap attached should you want to shoot and verify your sight adjustment before reinstalling it. Even with the lack of markings, this slide cap design is worthy of praise and easier to access than SIG Sauer's P320-based M17/M18 and X-series pistols.

The 509 frame features a high undercut at the rear of the triggerguard, and the magazine release is more pronounced than the FNS model.

The FN 509 Tactical shares the same mechanics and touchpoints as the standard 509. Though the profile of parts such as the slide lock lever, magazine release button, sights, slide serrations and the slide itself mark differences between the models, the internal structure and mechanical design of the 509 series is almost identical to FN's striker-fired FNS series. The extractor is perhaps the biggest mechanical difference, given that the FNS features a shorter, plunger-type extractor assembly and the 509 uses a spring-­loaded pivoting lever.

The FN 509's polymer frame features a recessed contour and a shelf for your trigger finger or support hand thumb to sit above the magazine release that provides easier access to the trigger for shooters with smaller hands or shorter fingers. The grip texture isn't aggressive but provides a confident grasp.

All FN 509s come with two backstrap options, flat and arched. Other companies include three, but this is fine because most people never experiment and those pieces are wasted. It also comes with an ambidextrous magazine release and testing noted that appropriate-length 509 and FNS magazines work interchangeably.

Shooting Impressions

The 509 Tactical's trigger measured less than 7 pounds. After 1,000 rounds, ours lightened by a half-pound. It's hinged in the middle and lacks the protruding safety lever in the middle that appears on almost every other striker-fired pistol. The 509 features a clean trigger press with a little bit of takeup that hits a wall. Once fired, there's little over-travel, and a subsequent shot features a ¼-inch reset with a consistent pull weight.

For me, adding a 3.5 MOA red dot improved G&A's already impressive accuracy results by an average of 15 percent. This is why I believe red dots are the future, as are suppressed firearms. It's time to join the movement, and the 509 series is an option I can stand behind.

FN 509 Tactical Specs

  • Type: Recoil-operated, striker-fired, semiautomatic
  • Cartridge: 9mm
  • Capacity: 17+1 rds. or 24+1 rds.
  • Barrel: 4.5 in., CHF; stainless steel; 1:10-in. twist, target crowned and threaded
  • Overall Length: 7.9 in.
  • Weight: 1 lb., 11.52 oz. (tested)
  • Grips: Enhanced texture; flat orarched backstrap (incl.)
  • Length of Pull: 2.55 in.
  • Finish: FDE; nitrocarburizing (steel)
  • Trigger: 6 lbs., 12.5 oz. (tested)
  • Sights: Trijicon Suppressor Night Sights; 3 dot; drift adj. mini red dot adapters (incl.)
  • MSRP: $1,050
  • Manufacturer: FN, 703-288-3500,
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