When it comes to choosing a reliable concealed-carry or duty pistol, balance between size, sighting options, and ergonomics is everything. We take a tactical, practical look at a compact striker-fired pistol built to bridge the gap between full-size capability and everyday carry comfort.
FN 509 MIDSIZE MRD [FDE]
Overview: Modern design, duty-grade pedigree
As two operators who favor gear that goes the distance, we appreciate the lineage behind the 509 platform. Built as a successor to the FNS series, the FN 509 MIDSIZE MRD [FDE] carries forward FN’s commitment to duty-grade reliability while offering a midsize footprint that helps when concealment matters. Its polymer frame reduces weight and improves corrosion resistance, making it a sensible choice for daily carry or a compact duty sidearm.
Shop this product to view current pricing and availability; MSRP-listed price for this model is $685.99, which situates it competitively among modern striker-fired pistols with optics-ready slides.
Key features and what they mean on the range
Optic-ready MRD slide and co-witness sights
The MRD designation means the slide is cut to accept red-dot optics using FN’s adapter plates. FN pairs that cut with suppressor-height iron sights to provide proper co-witnessing so you can ride the iron sights if the optic fails or you prefer aiming with irons. Optic not included, so plan for an optic purchase and proper plate configuration if you want a micro red-dot on the slide.
3-dot luminescent sights
Even with optic capability, the 509 MIDSIZE MRD [FDE] ships with 3-dot style luminescent sights. These provide quick sight acquisition in low light without relying on batteries, and they complement the suppressor-height rear and front setup for reliable sighting whether an optic is mounted or not.
Ergonomics: polymer frame, interchangeable backstraps, and ambidextrous controls
The polymer frame keeps weight down and resists corrosion. Interchangeable backstraps let you tune the grip to your hand size and shooting style — a critical feature for a midsize pistol with a shortened grip designed for easier concealment. Ambidextrous controls mean left- and right-handed shooters can index the slide release and magazine release without awkward transitions.
Midsize profile: 4-inch barrel and shortened grip
The 4-inch barrel delivers a balance of accuracy and compactness. The shortened grip aids concealment, reducing printing under cover garments while still maintaining a comfortable purchase for controlled follow-up shots. Two 15-round magazines are included, giving you solid capacity for a midsize pistol without a radical grip extension.
Tactical considerations and real-world applications
For concealed carriers who want more sight radius than a subcompact, the 4-inch 509 MIDSIZE MRD [FDE] provides better accuracy potential while remaining carry-friendly. For duty use, the optics-ready slide and suppressor-height sights make it adaptable for a variety of mission profiles, from plainclothes detail to uniformed roles where an optic may be preferred.
No manual safety — what that means
This model comes without a manual thumb safety, which streamlines the draw-and-engage process for many users. If you prefer a safer-with-safety approach, consider training rigorously on safe holster discipline and trigger control. The absence of a manual safety is deliberate in many modern defensive pistols to reduce complexity during high-stress engagements.
Durability and maintenance
FN’s polymer frame and corrosion-resistant surfaces help in harsh conditions. Routine maintenance — cleaning the barrel, slide rails, and recoil system after extended range sessions — will preserve reliability. The simple striker-fired mechanism is familiar to many shooters, making parts and aftermarket support broadly available.
Want to compare ergonomics and handling in person? View product details and pricing on the shop page to check specs and availability.
Who should consider the FN 509 MIDSIZE MRD [FDE]?
This pistol is a solid choice for those who want a compact footprint without sacrificing capacity and sight radius. If you value an optic-ready slide for speed and repeatable aim, prefer a corrosion-resistant polymer build, and want ambidextrous controls and interchangeable backstraps for comfort, the MIDSIZE MRD covers those bases.
Training and holsters
Invest in a holster designed for optics-ready slides if you plan to run a red dot. Because the grip is shortened for concealment, consider holsters that maintain muzzle and trigger coverage while allowing a smooth draw. Dry-fire practice with the included two 15-round magazines will help ingrain trigger control and reloads before you transition to live fire drills.
Final notes from two operators
From a practical standpoint, the FN 509 MIDSIZE MRD [FDE] brings duty-level ergonomics and modern sighting options into a package suited for daily carry. It’s priced at $685.99, which is competitive for a striker-fired pistol with an optics-ready slide and two 15-round magazines included.
Whether you’re equipping for off-duty carry, looking for a midsize range pistol with red-dot potential, or seeking a compact duty option with proven lineage, this model deserves a hands-on evaluation. Click to check the product page — Check availability — and if you can, get behind the trigger at the range to confirm fit, recoil control, and sight picture before purchasing.
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.
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