Complimenting the FN 509 Series is the FN 509 MRD fullsize pistol equipped with the company's patented Low-Profile Optics-Mounting System to users who want a full-sized duty-style pistol for personal or home defense. The pistol is chambered in 9mm and features a 4.5-inch cold hammer-forged barrel cut from the company's proprietary machine gun-grade stainless steel. The barrel features the FN 509-signature recessed target crown to protect rifling, maintaining accuracy and performance throughout the lifespan of the pistol. The full-sized slide and frame offer a secure grip and reduced recoil thanks to added weight and length of the slide.