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FN 509® MRD-LE

Available for law enforcement agencies only

The FN 509®  MRD-LE delivers more precision and versatility than any other duty-rated handgun. Building on the proven FN 509 lineup, the exclusive upgrades for law enforcement place every advantage in officers’ hands, with unmatched accuracy from a striker-fired handgun. Making up the new high-performance package is a conical striker, flat-faced duty-rated trigger and the FN Low-Profile Optics-Mounting System™ , for fast sight acquisition and consistent shot placement.

3-dot tritium sights co-witness with the MRD, for maximum sighting versatility and a clean sight picture, day or night. The industry’s most comprehensive and adaptable optics mounting platform, allows armorers to quickly mount common duty-rated optics.

The 509 MRD-LE is the choice for agencies who can’t settle for less than 100% reliability. With unmatched longevity in the most demanding trials, the FN 509 platform has been tested beyond 1-million rounds, chosen by departments for its compatibility with a wide variety of training and duty ammunition. With a polished feed ramp and chamber, consistent feeding and extraction exceeds every standard.

The smooth, drop-safe trigger compliments the perfect sight picture. FN’s precision trigger and high-performance striker, adapted from the FN 509 LS Edge™, has a positive wall before a clean break, improving accuracy for all officers. With a target-crowned, hammer forged barrel, a lifetime of tight groups is in reach.

FN 509® MRD-LE Spec Sheet

FN Optics Mounting System Quick Setup & Reference Guide

66-101287FN 509 MRD-LE NMS BLK/BLK NS 3X17845737014681
66-101934FN 509 MRD-LE NMS FDE/FDE NS 3X17845737018153


  • Caliber: 9mm
  • Operation: Double-action
  • Mag Capacity: 17 Rd.
  • Weight: 27 oz.
  • Barrel Length: 4.0"
  • Overall Length: 7.4"
  • Twist Rate: 1:10" RH
  • Height: 5.56"
  • Width: 1.35"
  • Trigger Pull: 4.5 lb. -6.0 lb.
  • Sight Radius: 5.79"

Primary Features

Patented FN Low-Profile Optics Mounting System fits most MRDs

Precision accuracy with unmatched sighting versatility

Duty-rated trigger breaks cleanly at 90°

Superior ergonomics for maximum speed and control


Quickly mount MRDs with the FN Low Profile Optics Mounting System™

3-dot tritium night sights co-witness to MRD, rear sight dovetail driftable

Front and rear cocking serrations for clean slide manipulations

External extractor, loaded chamber visual indicator


Drop-safe, duty-rated fire control group

Best-in-class flat-face trigger breaks cleanly at 90°

New, high-performance conical striker reduces trigger pull weight by ≈1-lbs.

4.5-lbs. to 6.0-lbs. trigger pull


4″ Target-crowned, hammer forged barrel for precision accuracy

Polished chamber and ramp for reliable feeding and extraction across ammunition types



Three interchangeable backstraps fit all hand sizes, improves sight recovery

Multi-surfaced texture for the perfect grip and faster follow up shots

Mil-Std 1913 rail fits all common weapon lights

Ambidextrous slide stop

Right-hand only magazine release

Black 17-rd magazines, high-vis low-friction follower



Three interchangeable backstraps

Three 17-round magazines

Four MRD mounting plates

Owner’s manual

Locking device

FN Ballistic case