FN 509M MRD Mid-Size 9mm Optic Ready Pistol 10+1 4" FDE

The FN 509M MRD delivers optic-ready capability in a mid-size platform engineered for versatility across duty, competition, and personal protection roles. This striker-fired pistol combines FN's military-proven reliability with enhanced ergonomics and mounting flexibility.

What Makes This Different

The 509M MRD features FN's Low-Profile Optics Mounting System with four different footprint patterns machined directly into the slide, eliminating adapter plates that add height and potential failure points. The recessed crown barrel design protects the muzzle while maintaining accuracy, while the ambidextrous controls accommodate both left and right-handed shooters without modification. This represents a significant upgrade over standard pistols that require aftermarket machining for optic mounting.

Key Features

• Low-Profile Optics Mounting System compatible with multiple red dot footprints
• 4-inch cold hammer-forged barrel with recessed target crown
• Flat Dark Earth PVD finish on slide with aggressive front and rear serrations
• MIL-STD-1913 Picatinny rail for tactical accessories
• Ambidextrous slide stop levers and magazine release
• Interchangeable backstraps for custom grip fit
• Two 10-round magazines included with extended base plates

The 509M MRD maintains consistent accuracy across various ammunition weights, with the 4-inch barrel length providing optimal balance between velocity and maneuverability. Law enforcement agencies have adopted this platform for duty carry, while competitive shooters appreciate the optic-ready slide and crisp trigger break. The polymer frame construction reduces overall weight to 27.9 ounces unloaded while maintaining structural integrity under high round counts.

Technical Specs

• Caliber: 9mm Luger
• Capacity: 10+1 rounds
• Barrel Length: 4.0 inches
• Overall Length: 7.4 inches
• Height: 5.5 inches
• Width: 1.35 inches
• Weight: 27.9 oz (unloaded)
• Frame: Flat Dark Earth polymer with textured grip panels
• Slide: Flat Dark Earth PVD coated stainless steel
• Trigger: Single-action striker-fired
• Sights: 3-dot luminescent
• Country of Origin: USA

FN's reputation for manufacturing military-grade firearms translates directly to civilian applications with the 509M MRD. The combination of optic compatibility, ambidextrous controls, and proven reliability makes this pistol suitable for serious applications where performance cannot be compromised.