The FN 509 Fullsize MRD is a duty-style 9mm pistol designed for dependable performance in personal protection, home defense, and professional applications. Its striker-fired operating system provides a consistent trigger pull, while the 4.5-inch cold hammer-forged barrel features FN's recessed target crown to help protect the rifling and preserve accuracy. The polymer frame and interchangeable backstraps support a secure, customizable grip, and the slide's textured profile helps provide positive handling with reduced felt recoil. The FN Low Profile Optics Mounting System makes the pistol ready for a compatible miniature red dot sight while retaining its fixed three-dot sights for a practical co-witnessing setup.

Key features

• Full-size 9mm striker-fired pistol with 17+1 capacity for duty and defensive use
• 4.5-inch cold hammer-forged barrel with a recessed target crown for durability and consistent accuracy
• FN Low Profile Optics Mounting System supports installation of a compatible miniature red dot sight
• Polymer frame with three interchangeable backstraps for a more customized grip
• Integrated trigger safety helps prevent unintended discharge
• Includes two 17-round magazines, four MRD mounting plates, three backstraps, a soft case, owner's manual, and gun lock

The FN 509 Fullsize MRD combines full-size handling, optics-ready capability, and adaptable ergonomics in a dependable 9mm pistol.