FN 509 MIDSIZE MRD 9mm 4 in Optic Ready | FN 66100588

The FN 509 Midsize MRD is an optic-ready 9mm midsize pistol equipped with the FN Low Profile Optics Mounting System for direct mounting of multiple miniature red dot sights. It pairs a four-inch barrel and slide with a matte black polymer frame and co-witness iron sights in a package intended for everyday carry and range use. A compact red dot such as the Holosun 507K is a practical optic choice under $1000 that will mount to the MRD system without extensive modification. Applications include concealed carry/EDC and precision practice or competition at the range.

Product Specifications

• The caliber is 9mm Luger.
• The barrel measures 4 inches.
• The action is Semi-Auto.
• The optic footprint supports multiple mounting patterns.
• The slide is Optic Ready/Serrated.
• The frame is made from polymer.
• The finish is matte black.
• The firearm includes two magazines.
• The sights are black co-witness iron sights.
• Overall length is 7.40 inches.
• The rifling twist rate is 1:10.
• This model ships with an optic mounting system and two magazines.
• UPC is 845737010744.
• The ATF model is 509.
• Designed for right-hand shooters.

The FN 509 Midsize MRD balances carry concealability with features drawn from full-size service pistols: an optics-capable slide, enhanced grip texture, interchangeable backstraps, and a flat-faced trigger to support consistent follow-up shots. The package is practical for shooters seeking a reliable, duty-grade platform in a midsize form factor with direct-mount optics capability.