FN America 509 MRD, Striker Fired, Semi-automatic, Polymer Frame Pistol, Mid-Size, 9MM, 4" Barrel, Matte Finish, Black, Inlcudes Holosun 407C Red Dot Sight, Non-Manual Safety, Optic Height Sights, 10 Rounds, 2 Magazines 66-101928 66101928

FN America 509 MRD — Mid-Size 9mm Pistol | 4" Barrel | Striker-Fired | Black Matte | Optics-Ready Slide with Holosun 407C Included | Non-Manual Safety | Optic-Height Sights | 10+1 Capacity | 2 Magazines | 66-101928 (66101928) | UPC: 845737018351 Meet the do-everything, carry-everywhere FN. The FN 509 MRD Mid-Size pairs FN’s battle-proven striker-fired reliability with an optics-ready slide and factory-mounted Holosun 407C red dot so you’re faster to the first shot and quicker on follow-ups. With a 4" cold hammer-forged barrel, non-manual safety system, and optic-height iron sights that co-witness with the dot, this 10-round package is built for concealed carry, duty-grade performance, and home defense—straight out of the box. Why Choose the FN 509 MRD Mid-Size (with Holosun 407C)? Dot-ready from Day One: No hunting for plates or guessing on height—your Holosun 407C is included and ready to mount/zero for rapid target acquisition and both-eyes-open shooting. Carry-smart size: The mid-size frame and 4" barrel balance shootability, recoil control, and concealment. Duty pedigree: The FN 509 family stems from rigorous LE/military trials—expect reliability, durability, and consistent trigger performance. Non-manual safety simplicity: Internal safeties with a clean, consistent striker-fired press—no external lever to manipulate under stress. True co-witness: Optic-height iron sights provide a daylight backup sighting system through the red dot window. Key Features & Advantages Caliber & Capacity: 9mm Luger, 10+1 rounds (two 10-rd magazines included) for compliance-friendly carry. Barrel: 4" cold hammer-forged barrel for long service life and tight mechanical accuracy. Slide & Finish: Matte black slide with front/rear cocking serrations for confident manipulations in rain, sweat, or gloves. Optics-Ready MRD Slide: Factory footprint and mounting system pair with the included Holosun 407C (multi-coated glass, long battery life, shake-awake—model-dependent features). Sights: Optic-height steel sights deliver lower-third co-witness for immediate transition if your dot is obscured. Trigger & Controls: Crisp striker-fired trigger; ambidextrous slide stop and reversible mag release support left- or right-handed shooters. Frame: Black polymer frame with interchangeable backstraps (where equipped) for customizable grip size; aggressive texturing for recoil control. Non-Manual Safety: Internal striker block and drop safeties—no external thumb safety for streamlined operation. Accessory Rail: Picatinny dust-cover rail for a white light or laser. Note: Exact plate/adapter style, backstrap count, and Holosun 407C variant may vary by lot. Always confirm your unit’s contents on the box label and manual. Performance You Can Feel Faster first-shot sight picture: With the 407C installed and zeroed, simply present and dot—no rear/front alignment required. Confidence in low light: Pair a weapon light on the rail with the red dot for faster identification and aiming in the dark. Manageable recoil, faster splits: The 4" barrel and frame geometry help keep the muzzle flat for quicker follow-ups and tighter groups. Glove-friendly controls: Serrations, large trigger guard, and ambi controls make manipulations straightforward in any season. Ideal Use Cases Concealed Carry (CCW): Mid-size footprint conceals easily with a quality holster, while optic-height sights maintain redundancy. Home Defense: Mount a compact WML, keep both-eyes-open with the dot, and rely on FN’s proven reliability. Range & Training: Learn red-dot pistol fundamentals, track the dot in recoil, and log consistent reps with the included two magazines. Duty/Plainclothes: Serious, low-maintenance set-up with professional reliability and co-witness backup irons. What’s in the Box FN 509 MRD Mid-Size 9mm pistol, black Holosun 407C red dot sight (battery included; model features vary) Two (2) 10-round magazines Optics mounting hardware/plate (model dependent) Lock, manual, and factory case Zeroing & Setup Tips Mount & Torque: Install the 407C per Holosun/FN torque specs; use threadlocker where specified. Co-Witness Check: Verify lower-third co-witness with optic-height irons; adjust dot elevation/windage as needed. Confirm at Distance: Zero at 10–15 yards for defensive use (or your preferred distance), then verify at 25 yards. Battery Discipline: Record the install date; replace the battery on a schedule even with shake-awake. Holster Fit: Choose a 509 MRD + optic-compatible holster with clearance for optic-height sights and mounted WML (if used). Specifications (Quick View) Model: FN 509 MRD Mid-Size SKU/Part #: 66-101928 (also listed as 66101928) UPC: 845737018351 Action: Striker-fired, non-manual safety Caliber: 9mm Luger Barrel Length: 4" Frame/Slide: Polymer frame, matte black slide Sights: Optic-height iron sights, co-witness with included Holosun 407C Capacity: 10+1 (two 10-rd magazines included) Rail: Picatinny accessory rail Controls: Ambi slide stop, reversible mag release (Overall length, height, weight, trigger specs, and exact optic features may vary. Refer to the included manual for authoritative values.) Compliance, Safety & Maintenance Know your laws: Verify local/state regulations regarding optics, magazine capacity, and transport. Routine maintenance: Keep the pistol clean and lightly lubricated; re-check optic screws after first 200 rounds. Safe storage: Use a secure, locked storage solution; never store the firearm loaded where unauthorized access is possible. Training: Regular dry fire and live fire with your chosen carry ammo to validate zero and reliability. SEO-Friendly Highlights (What Shoppers Search) FN 509 MRD mid-size 9mm with Holosun 407C FN 509 4" optics-ready pistol black 10 round FN 509 red dot co-witness optic height sights Striker-fired FN 509 non-manual safety 66-101928 845737018351 FN America 509 MRD package 2 mags The Bottom Line The FN 509 MRD Mid-Size (66-101928) gives you a professional-grade, optics-ready 9mm with the Holosun 407C already in the box—no guessing, no parts hunt, just mount, zero, and train. With 10-round capacity, optic-height irons, and FN’s proven reliability, this is a modern defensive handgun that’s ready for serious work the day you bring it home. The End