The FN 509MT is a striker-fired 9MM Luger pistol with a 4.5-inch barrel, 15+1 capacity, and a matte black finish. It carries three-dot night sights at suppressor height and ships without a manual safety. 
 

Key Specifications 

• SKU: 2024020062 
• UPC: 845737018405 
• Brand: FN 
• Model Name: 509MT 
• MPN: 66101936 
• Caliber: 9MM LUGER 
• Action: Striker Fire 
• Capacity: 15+1 RD 
• Barrel Length: 4.5" 
• Overall Length: 7.90" 
• Weight: 1.7 lbs 
• Sights: 3-Dot Night / Suppressor Height 
• Grip Type: Black Interchangeable Backstrap 
• Trigger Type: Standard 
• Safety Feature: No manual safety 
• Finish Color: Matte Black 
• Condition: New in Box 
   

Detailed Features 

The striker-fire action resets quickly between shots and provides a consistent pull that does not vary between first and subsequent rounds. Suppressor-height sights sit tall enough to co-witness over most miniature red dot optics, which is useful if the platform is used with a threaded barrel and suppressor. 
 
The interchangeable backstrap system lets users adjust grip circumference to fit different hand sizes without replacing the entire grip module. At 1.7 lbs the pistol is manageable for all-day carry and does not fatigue the shooter during long range sessions. No manual safety simplifies the draw and presentation for users trained on striker-fired platforms. 
 

Usage 

The 509MT is suited for duty carry, home defense, and competitive shooting. The night sights and no-manual-safety configuration make it straightforward to deploy quickly under stress.

Owners credit FN's construction quality as the first thing they notice about the 509MT. The fit and finish are generally described as duty-grade, with components that feel well-matched and solid.

Ergonomics receive positive feedback. The grip texture and interchangeable backstraps help most hand sizes find a comfortable hold, and the controls are easy to reach without adjusting grip position.

Accuracy at short and medium distances is consistently rated well. The 4.5-inch barrel delivers reliable performance, and many owners use the 509MT as both a range gun and a carry option.

Night sights are a frequently mentioned advantage. Owners who prioritize low-light readiness appreciate having them factory-installed rather than having to source and swap aftermarket sights.

The trigger generates some debate. A subset of owners find the pull heavier than other striker-fired pistols they've used, and a few note that the reset feels less defined than competing options. Most describe it as adequate rather than noteworthy, and aftermarket options exist for those who want a lighter or crisper feel.

Reliability during break-in has been inconsistent for a small number of owners, with occasional issues on specific ammunition types early in the pistol's life. Most report that function becomes consistent after 200-300 rounds.

Grip texture feedback splits between those who find it provides good purchase and those who prefer more aggressive texturing for use in wet conditions. Price is generally viewed as appropriate for a duty-grade FN pistol.