The FN 510 MRD in black is a double-action-only 10mm Auto pistol with a 4.1-inch cold hammer-forged barrel and an FN low-profile optics mounting system. Capacity is 15+1 rounds. Weight is 31 oz (1.9 lbs) and overall length is 7.7 inches. The polymer frame has interchangeable backstraps and the ambidextrous slide stop works for both hands. No manual safety. Picatinny rail on the dust cover for lights and lasers. 
 

Key Specifications 

• Brand: FN 
• Model Name: 510 MRD 
• Caliber: 10mm Auto 
• Action: DAO (Double Action Only) 
• Capacity: 15+1 rounds 
• Barrel Length: 4.1 inches 
• Overall Length (OAL): 7.7 inches 
• Weight: 31 oz (1.9 lbs) 
• Sights: Driftable Steel Co-Witness 
• Grip Material: Black Textured Polymer 
• Safety Features: No Manual Safety 
• Finish Color: Black 
• Condition: New in Box 
   

Detailed Features 

1. Cold Hammer Forged Barrel: 4.1-inch barrel with polished feed ramp and chamber for smooth cycling. Extended durability compared to button-rifled alternatives. 
2. FN Low-Profile Optics Mounting System: Accepts diverse optic footprints while co-witness steel iron sights remain usable. 
3. Ergonomic Frame: Polymer frame with interchangeable backstraps for grip customization. 
4. Ambidextrous Slide Stop: Functions for left- and right-handed operation. 
5. Picatinny Rail: Full-length rail for flashlights, lasers, or other tactical accessories. 
    

Usage Scenarios 

1. Self-defense at home: 15+1 rounds of 10mm AUTO in a controllable platform. 
2. Competitive shooting: Factory optics-ready setup reduces setup time for red-dot-equipped competition divisions. 
3. Outdoor carry: 10mm AUTO is a practical choice in areas where encounters with large animals are possible.

Owners of the FN 510 MRD black variant consistently report good reliability across different 10mm loads. The pistol cycles cleanly and the 10mm caliber delivers the stopping power the cartridge is known for. The optics-ready design gets frequent positive mention -- straightforward red dot mounting is a legitimate convenience.

Ergonomics are generally comfortable. The grip texture provides a secure hold without being rough, and the dimensions feel manageable for most shooters despite the pistol's size. The 15+1 capacity is a common talking point, particularly for those weighing it against other 10mm options.

The main criticisms are weight and price. At 31 oz the 510 is heavier than many polymer-frame alternatives, which affects carry comfort over long periods. The price is toward the higher end of the 10mm segment, prompting some buyers to compare it against cheaper options with similar specs. Recoil with full-power 10mm is noticeable, though most experienced owners find the FN 510's mass helps control it. Overall sentiment is positive among buyers who specifically want a 10mm platform with optics capability built in.