The FN 509C Tactical is a compact 9mm striker-fired pistol in Flat Dark Earth finish. It has a 4.32-inch threaded barrel, three-dot night sights, and FN's Low Profile Optics Mounting System for mounting red dot sights. Capacity is 10+1 rounds. Overall length is 7.4 inches and weight is 26.2 oz (1.6 lbs). The grip ships with interchangeable backstraps. 
 

Key Specifications 

• Brand: FN America 
• Model Name: 509C Tactical 
• Caliber: 9mm Luger (9x19 Para) 
• Action: Double Action/Semi-Auto Striker Fire 
• Capacity: 10+1 rounds 
• Barrel Length: 4.32 inches (threaded) 
• Overall Length: 7.4 inches 
• Weight: 26.2 oz (1.6 lbs) 
• Finish: Flat Dark Earth (FDE) 
• Sights: FN Low Profile Optics Mounting System with Night Sights 
   

Detailed Features 

 
The 4.32-inch threaded barrel accepts suppressors and compensators without an adapter. The FN Low Profile Optics Mounting System allows direct mounting of red dot sights. Night sights are the factory standard and work in low-light without additional equipment. Interchangeable backstraps let you adjust grip width to fit your hand. The frame is polymer; the slide is stainless steel. 
 
The 509C Tactical is the compact version of the 509 line and fits in a smaller footprint than the full-size, though the threaded barrel extends the overall length compared to a standard compact.

The FN 509C Tactical in FDE draws consistent positive reviews, with a few recurring concerns.

Reliability gets mentioned most often -- owners report it feeds a wide range of ammunition without issues. The ergonomics are frequently praised; the grip shape and interchangeable backstraps give it a comfortable fit across different hand sizes. The threaded barrel is a real draw for suppressor users and those who want to run a muzzle device. Night sights are a factory inclusion that buyers appreciate, as many competing pistols require an aftermarket upgrade for the same capability.

The FDE finish gets positive attention from buyers who want something other than black. Aftermarket support is good, with holsters, lights, and sight options widely available.

On price, some buyers note the 509C Tactical costs more than comparable compact pistols. Most owners feel the feature set and FN's build quality justify it, but it is a premium over basic striker-fired options.

Overall sentiment is positive, with the threaded barrel, optics mounting system, and night sights being the most-cited reasons for choosing it over competitors.