FN 509M Tactical | 9mm | 4.5″ Threaded | 5x10rd Mags

The FN 509M Midsize Tactical is an optics-ready 9mm midsize pistol with a 4.5-inch threaded barrel and a five-magazine package intended for informed shooters seeking a versatile carry-size platform. It ships with multiple 10-round magazines, a soft case, and interchangeable backstraps to tailor grip ergonomics. The slide is factory-milled for FN’s Low-Profile Optics-Mounting System and accepts a wide range of micro red-dot sights; a Trijicon SRO is a suitable optic option under $1,000 for users who want a durable, full-field red-dot solution.

Product Specifications

• The UPC is 845737017422.
• The manufacturer part number is 66-101712.
• The model is listed as FN509M.
• The caliber is 9mm.
• The barrel length is 4.5 inches.
• The thread pattern is 1/2×28.
• The optic footprint is documented as multiple to accept a range of micro red dots.
• The frame material is polymer.
• The finish/color is black.
• The magazine capacity is 10 rounds.
• The number of magazines included is 5.
• The sights are specified as night sights.
• The overall length is 7.9 inches.
• Included accessories list a FN soft case, two interchangeable backstraps, and five 10-round magazines.
• Other notable features include optics-ready slide and a threaded barrel for suppressor compatibility or muzzle devices.

This midsize pistol balances shootability and concealability while providing an optics-ready platform and threaded-barrel flexibility. Controls and ergonomics are designed for fast sight acquisition and repeatable follow-up shots, and the included magazine package supports extended range sessions or duty use out of the box. The combination of a machined slide footprint, suppressor-capable barrel, and multiple magazines makes this a practical choice for everyday carry and duty roles where a compact, capable 9mm is desired.