The FN 509 Midsize MRD is a striker-fired 9mm pistol with a 4-inch cold hammer-forged stainless steel barrel and an overall length of 7.4 inches. It weighs 26.9 ounces and holds 15+1 rounds, with two magazines in the box. The slide accepts compatible red dots through FN's Optics Mount System, and the grip accepts interchangeable backstraps to adjust the fit. Standard fixed sights are fitted when no optic is mounted.

This model is a service-style 9mm with a shortened grip, so it sits between a full-size duty pistol and a compact carry gun. The midsize frame offers a practical balance of capacity and concealability, and the optics-ready slide suits owners who train with a red dot. The backstraps let the grip be tailored to the shooter's hand without changing the pistol itself.

Key features

• Striker-fired 9mm semi-automatic action
• 4-inch cold hammer-forged stainless barrel
• Optics-ready slide with FN Optics Mount System
• 15+1 capacity, two magazines included
• Interchangeable backstraps for a custom grip fit

This pistol ships to your chosen Florida FFL dealer, where you complete Form 4473 and the background check.