FN 509 BLK Semi Auto: Compact & Concealable Handgun

When you need a compact, concealable handgun that’s built on duty-grade DNA, you want something that balances reliability, ergonomics, and modern features. A pistol that works as hard in a daily carry role as it would in a duty bag requires thoughtful design and proven engineering — no gimmicks, just performance.

FN 509 MIDSIZE MRD [BLK]

Shop this product to view the firearm and accessories on the vendor page.

What makes the FN 509 MIDSIZE MRD [BLK] stand out

The FN 509 MIDSIZE MRD [BLK] continues FN’s evolution of striker-fired pistols, following the legacy of the FNS line while bringing modern refinements. It’s designed as a duty and defensive handgun with a polymer frame for weight savings and enhanced corrosion resistance — important when you carry daily or operate in variable environments. Ambidextrous controls and interchangeable backstraps let shooters fine-tune the grip and manipulations to match hand size and shooting style, while the shortened grip and 4-inch barrel on the Midsize variant make it far easier to conceal than full-size duty pistols.

Key features explained

Polymer frame and ergonomics

The polymer frame of the FN 509 MIDSIZE MRD [BLK] reduces overall weight without sacrificing rigidity. Interchangeable backstraps allow users to adjust grip circumference, improving sight alignment and recoil control for a wide range of shooters. The shortened grip profile aids concealment while still accepting full-capacity magazines.

Controls and safety

FN outfitted this model with ambidextrous controls to ensure left- and right-handed shooters have the same access and ease of operation. This particular MRD model does not include a manual safety, which streamlines draw-and-fire transitions for users trained in a no-manual-safety carry setup. That configuration emphasizes consistent trigger discipline and a holster solution that protects against unintentional engagement.

MRD optic-ready slide and sighting system

The MRD designation signals an optic-cut slide designed to accept FN adapter plates and a variety of micro red dot optics. The slide is paired with suppressor-height iron sights to facilitate proper co-witness when an optic is mounted, making this platform ready for modern sighting setups out of the box. The optic-ready approach gives the end user a fast and repeatable sight picture for defensive shot placement.

Barrel length, concealability, and magazines

The Midsize variant’s 4-inch barrel offers a solid balance between ballistic performance and concealability. The shortened grip reduces printing under cover garments while still allowing a reliable purchase on the pistol. FN includes two 15-round magazines with this model, providing substantial capacity for a midsize defensive pistol without resorting to extended baseplates that could compromise concealment.

Performance expectations and practical use

As a successor to the FNS series, the FN 509 MIDSIZE MRD [BLK] targets duty-level durability with defensive shootability. Striker-fired pistols are known for consistent trigger characteristics and straightforward maintenance — qualities important for a defensive handgun intended for frequent carry or service use. The all-black finish minimizes visual signature and resists wear in everyday use.

Caliber information is not specified on the listing for this particular configuration; prospective buyers should confirm available caliber options on the product page before purchasing, especially if they have a strong preference for a specific chambering. For authoritative details, View product details and pricing on the shop page.

Training, holster selection, and accessories

When you carry a pistol like the FN 509 MIDSIZE MRD [BLK], training is the multiplier that makes the hardware effective. Practice draw, reloads, malfunction drills, and transitions with the optic installed if you plan to use one. Holster selection should account for the MRD footprint and suppressor-height sights; many manufacturers now offer holsters tailored to optics-ready slides but confirm compatibility before buying. The included magazines make a good baseline; adding one or two spare mags and a compact magazine carrier rounds out a practical setup.

Check current availability

Pricing and purchase considerations

Listed at $661.99, the FN 509 MIDSIZE MRD [BLK] positions itself competitively among optic-ready midsize duty pistols. The package includes two 15-round magazines, and the MRD configuration reduces the need for slide milling after purchase if you intend to run a micro red dot. As with any firearm purchase, verify local laws, check retailer policies, and ensure you select the correct configuration for your intended use.

Final notes from the range

From a practical standpoint, the FN 509 MIDSIZE MRD [BLK] is a no-nonsense choice for someone seeking a modern, optic-ready midsize pistol with duty-grade roots. It blends FN’s proven ergonomics and reliability with the flexibility of an MRD-ready slide and user-adjustable fit. Whether you prioritize concealment, capacity, or the option to run a micro red dot, this model addresses those needs without excess complexity.

Ready to own one? Shop this product on the retailer page to review specs, confirm configurations, and complete your purchase.

People Also Ask

What makes this product stand out from competitors?

This product offers superior quality and innovative features that set it apart in the market. Its design focuses on both performance and reliability, making it a top choice for professionals and enthusiasts alike.

Is this product suitable for beginners?

Yes, this product is designed with user-friendly features that make it accessible to beginners while still offering advanced capabilities for experienced users.

What warranty or support is available?

The product comes with comprehensive warranty coverage and excellent customer support to ensure your satisfaction and peace of mind.

How does this compare to similar products in its price range?

This product offers exceptional value for its price point, providing features and quality that typically cost significantly more in comparable alternatives.

What maintenance is required?

Minimal maintenance is required thanks to the product’s durable construction and quality materials. Regular cleaning and occasional inspections will keep it performing optimally.