FN 509 Midsize MRD 9mm Luger 4in FDE Pistol - 15+1 Rounds - This evolution of the FN 509 Midsize, now featuring the FN Low Profile Optics Mounting System, gives you the option of direct mounting more than 10 different miniature red dot optics to your concealed carry pistol. The FN 509 Midsize MRD features a four-inch barrel and slide with optics mounting package, a midsized frame, standard 15-round capacity and is compatible with larger capacity FN 509 magazines with use of a sleeve. The improved controls aid in manipulation, the new improved texturing on the two included backstraps provides better recoil management, and a new flatter faced trigger allows for more controllable trigger press and cleaner break. Twist Rate: 1: 10in Striker-Fired Auto Loader Fully Ambidextrous Easily Racked External Extractor Cold Hammer-Forged Stainless Steel MIL-STD 1913 Accessory Mounting Rail Improved Flatter Face Trigger Ships With: Two Interchangeable Backstraps Two 15 Round Magazines Owners Manual Locking Device FN Logo Soft Case Browse FN 509 9mm pistols for sale at Sportsman's Warehouse.