Gun Reviews

FN 509

Posted Jun 16, 2023
Cover Image for FN 509

FN Herstal has long been a pillar of top of the line firearms innovation. From the FN Five-seveN to the legendary FN SCAR rifle and to now the FN 509, the company has produced firearms for the common consumer and the battlefield elite.

FN 509 is no exception. This striker-fired 9mm pistol is a result of many years of work by one of the premier firearms manufacturers on the market today. FN 509 is a strong, lightweight polymer-framed pistol engineered for maximum accuracy and reliability.

The fit and finish of this firearm are second to none. The 509's stainless steel slide has been designed to NITRON finish, giving it a perfect semi-matte black look that is far more pleasing then other finishes on the market today. The slide also houses FN's signature slide serrations that provide positive traction even when your hands are sweaty.

The frame of the 509 is constructed from a lightweight but very strong polymer. The frame of the pistol is designed with interchangeable backstraps to fit to whatever size fits best. Interchangeable backstraps is a feature traditionally seen in custom-made firearms, and having such a feature as standard on an off-the-shelf gun is certainly a plus.

FN has also done an excellent job engineering this trigger. The 509 features a polished stainless steel trigger that is a pleasure to pull on. The trigger pull is smooth and consistent, with a short and crisp break. FN has also angled the trigger in such a way that it targets the web of your hand the optimal angle for maximum comfort and accuracy.

The ergonomics of the FN 509 are top notch. The slide is contoured to provide a comfortable grip profile while the interchangeable backstraps provide a secure fit to your hand. The gun also has two ambidextrous thumb safeties that can be engaged with either hand for optimum safety and convenience while firing.

In addition to the great fit and feel of the FN 509, the pistol includes a number of features that make it stand out from the crowd. The gun features both a reversible magazine release and an interchangeable backstrap for added convenience. The 509 also features FN's signature low profile optics mounting system that allows you to quickly and easily mount a mini red dot sight without having to buy an aftermarket mounting system.

The 509 also offers impressive accuracy out of the box. FN has equipped the FN 509 with a 4.7in (12cm) barrel that provides exceptional performance, and the 509's three-dot sights make it easy to gain a good sight picture without much effort.

The pistol also includes three 17-round magazines for added convenience, so you can switch out quick reloads easily.

In terms of safety, the FN 509 offers several features to make sure your pistol is used and stored safely. The 509 features a loaded chamber indicator to visibly and tactilely alert you as to whether or not a round is in the chamber. The 509 also has a magazine safety system that prevents fired rounds from being chambered and requires an empty magazine to be inserted before a round can be chambered.

Lastly, the FN 509 is a remarkably reliable pistol. FN has tested the 509 for more than 20,000 rounds without any stoppages or malfunctions. This is a testament to FN's commitment to producing excellent firearms and is a testament to how well this pistol has been engineered.

In conclusion, the FN 509 is a remarkably accurate and reliable firearm. The pistol's features combine to make an impressive firearm, one that is suitable as a duty sidearm or as a concealed carry option. The 509's ergonomics are second to none and the reliability of this gun is unparalleled in its class. No matter what your purpose, the FN 509 is a great choice for a reliable and accurate handgun.

Pros & Cons


  1. Reliability: FN's cold hammer-forged barrels are known for their durability, resulting in consistent accuracy.
  1. Ergonomics: The FN 509 has a comfortable grip angle and texture that make it easy to maintain control over during shooting.
  1. Modularity: Being able to customize various aspects of the FN 509 make it uniquely suited for different tasks and environments.
  1. Accuracy: The FN 509 has an optimal barrel length that helps with accuracy and stability of the shot.


  1. Magazine Capacity: The FN 509 is limited to a 17-round capacity, making it difficult to compete with more than 17 magazine carrying competitors.
  1. Trigger: Many shooters find the FN 509's trigger to be slightly too gritty.
  1. Price: FN 509s can be quite pricey, being on the higher end of the market.
  1. Weight: The FN 509 is on the heavier side, weighing in at twenty-six ounces loaded.

Who Should Buy

FN 509 is a high-end, full-size 9mm handgun. It is a very reliable and high-performance weapon that is often seen in competitive shooting competitions. It is a great choice for beginner and experienced shooters alike who want a dependable and accurate handgun for personal protection or for target shooting. It is also ideal for those who want a gun for concealed carry.

However, it is not recommended that first-time buyers purchase a FN 509. The firearm is expensive and requires more expertise to operate than a budget-friendly handgun. Additionally, proper training and instruction is important for those who own this weapon in order to ensure safe and effective handling. Lastly, those who live in states where magazines with more than 10 rounds are illegal may want to stay away from FN 509 due to its extended capacity magazines.

FeatureFN 509Smith & Wesson Performance Center PC1911Wilson Combat CQB Tactical LEHeckler & Koch HK 416
Weapon TypeSemi-automatic PistolSemi-automatic PistolSemi-automatic PistolSemi-automatic Rifle
Caliber9mm.45 ACP.45 ACP5.56mm NATO
Capacity10+1, 15+1, 17+1 or 24+1 rounds7+1 rounds8+1 rounds30 rounds
Weight1.8 lbs.2.44 lbs.2.13 lbs.6 lbs.
Barrel Length4”5”5”16.5”
Magazine ReleaseReversibleStanadardStandardButton Release
Safety3 Auto Safeties and Trigger SafetyThumb and Grip SafetyThumb and Grip SafetySafe, Semi-Auto, and Full Auto

Features / Specs

•Model: FN 509

•Caliber: 9mm Luger

•Capacity: 10, 17, or 24 Rounds

•Action: Striker Fired

•Barrel Length: 4.0"

•Weight: 27.9 oz. Unloaded

•Overall Length: 7.4"

•Front Sight: Fixed Steel 3-dot

•Rear Sight: Low Profile Optic Ready

•Frame Finish: Flat Dark Earth Polymer Frame

•Slide Finish: Nitron Black Stainless Steel

Popular Accessories

The most popular accessories for the FN 509 are:

  1. Extended Magazines
  1. Grip Extensions
  1. Optic Mounting Plates and Red Dot Sights
  1. Lights and Lasers
  1. Holsters
  1. Magazine Couplers
  1. Magazine Loaders
  1. Slides
  1. Aftermarket Triggers
  1. Threaded Barrels


The FN 509 is an incredibly accurate handgun—many owners have reported remarkable accuracy from the platform. From the factory, this handgun offers five inch and four inch barrels, both of which are match grade and feature hammer-forged rifling, which helps deliver a very high degree of accuracy. Furthermore, the FN 509’s ergonomics and low bore axis are great for consistent shooting. The trigger on the FN 509 is designed to promote accurate shooting and is touted as one of the best factory triggers available on any handgun. Additionally, the gun's aggressive grip texturing and slim grip make it easy to control, furthering accuracy. Put all this together and you have a pistol that is capable of delivering excellent accuracy. The FN 509 is a great choice for anyone looking for a reliable, accurate and versatile handgun.

Video Reviews
Cover Image for FN 509 Midsize Review: The Best 9mm Pistol Out Of The Box
FN 509 Midsize Review: The Best 9mm Pistol Out Of The Box
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FN 509 Review: Better Than A M&P Or Glock?
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