Kansas Gunshop is a Wichita, KS-based retailer specializing in firearms and accessories. The FN 509 MRD-LE 9mm Semi-Auto Pistol is a duty-grade, optics-ready handgun designed for optimal performance. Its robust construction and versatile optics mounting system set it apart. Available now at Kansas Gunshop for $749.0.
Reviewed by Derek, Owner & FFL Holder at Kansas Gunshop. Kansas-licensed FFL dealer since 2008, NRA Range Safety Officer.
Last updated: April 2026
What are the specifications of the FN 509 MRD-LE?
| Product Type | Semi-Automatic Pistol |
|---|---|
| Caliber | 9mm Luger |
| Operation | Striker-fired |
| Magazine Capacity | 17+1 / 24+1 (includes two 17-round and one 24-round magazine) |
| Barrel Length | 4.5″ Cold Hammer-Forged, Threaded |
| Overall Length | 7.9″ |
| Weight | 27.5 oz (empty) |
| Sights | Co-witnessing Suppressor-Height Trijicon 3-dot Tritium Night Sights |
| Optics Mounting | FN Low-Profile Optics Mounting System™ |
| Frame Material | Polymer |
| Slide Material | Stainless Steel |
| Finish | Black (Nitride) |
| Trigger Pull | 5.5 – 7.5 lbs |
| Country of Origin | USA |
| Condition | New |
| SKU | 66-100869 |
What are the key features of the FN 509 MRD-LE?
The FN 509 MRD-LE is built with law enforcement and serious shooters in mind, offering a robust set of features. The 4.5-inch cold hammer-forged barrel is threaded, making it ready for a suppressor right out of the box, which is a significant advantage for those looking to reduce muzzle blast and sound. The FN Low-Profile Optics Mounting System™ is a standout, allowing for a wide array of miniature red dot sights to be mounted directly to the slide, maintaining a low bore axis for better recoil management. This system includes multiple plates to ensure compatibility with most popular optics on the market. Co-witnessing suppressor-height Trijicon 3-dot tritium night sights provide a reliable backup and are visible over most mounted optics, ensuring you always have a sight picture. The pistol comes with two 17-round magazines and one extended 24-round magazine, offering ample capacity for duty or range use. Its ambidextrous slide stop and magazine release cater to both right and left-handed shooters, adding to its versatility. The aggressive grip texture ensures a secure hold even in adverse conditions, and interchangeable backstraps allow for a customized fit to different hand sizes.
Who is the FN 509 MRD-LE for?
- Buy it if:
- You are a law enforcement officer seeking a reliable, duty-ready pistol with optics capability.
- You are a competitive shooter who values an optics-ready platform and a threaded barrel for compensators or suppressors.
- You want a robust 9mm handgun with high capacity for self-defense or home protection.
- You appreciate the modularity of an optics-ready system and the flexibility of a threaded barrel.
- You need a pistol that comes with suppressor-height night sights for co-witnessing with an optic.
- Skip it if:
- You prefer a more compact pistol for concealed carry (see our compact handguns for alternatives).
- You are on a very tight budget and do not require all the duty-grade features (consider other entry-level 9mm pistols).
- You are looking for a handgun primarily for target shooting without any intention of using an optic or suppressor.
What are the advantages and disadvantages?
- ✅ Integrated Low-Profile Optics Mounting System™ for broad compatibility.
- ✅ Threaded barrel comes standard, ready for suppressors or compensators.
- ✅ Suppressor-height Trijicon night sights provide excellent visibility and co-witness with optics.
- ✅ Ambidextrous controls enhance usability for all shooters.
- ✅ Comes with generous magazine capacity, including an extended 24-round option.
- ✅ Robust polymer frame and stainless steel slide ensure durability.
- ❌ The grip texture, while effective, might be too aggressive for some users without gloves.
- ❌ Its size and weight, while suitable for duty, might be less ideal for deep concealment compared to smaller models (consider a subcompact 9mm).
- ❌ The trigger, while consistent, is not a match-grade trigger out of the box for precision target work.
How does the FN 509 MRD-LE compare to other pistols?
| Feature | FN 509 MRD-LE | Glock 19 MOS | Springfield Armory Echelon |
|---|---|---|---|
| Material | Polymer Frame, Stainless Steel Slide | Polymer Frame, Steel Slide | Polymer Frame, Steel Slide |
| Quality | Duty-grade, robust construction | Reliable, proven design | Modular, modern design |
| Compatibility | FN Low-Profile Optics Mounting System™ (multiple plates), Threaded Barrel | MOS (Modular Optic System) plates, non-threaded barrel standard | Variable Interface System (VIS) for optics, threaded barrel optional |
| Shipping | Ships from Wichita, KS | Varies by retailer | Varies by retailer |
| Lifespan/Durability | Designed for high-round count, duty use | Known for extreme durability and longevity | Built for hard use, new to market |
| Price | $749.0 | ~$650-750 (depending on configuration) | ~$679-799 (depending on configuration) |
Frequently Asked Questions
What is the FN Low-Profile Optics Mounting System?
The FN Low-Profile Optics Mounting System is a proprietary system that allows for direct mounting of various miniature red dot sights to the slide of the FN 509 MRD-LE. It includes a series of interchangeable plates to accommodate a wide range of popular optics, ensuring a secure and low-profile fit.
Does the FN 509 MRD-LE come with a threaded barrel?
Yes, the FN 509 MRD-LE model features a 4.5-inch cold hammer-forged threaded barrel as a standard feature, making it ready for suppressor or compensator attachment.
What kind of sights does the FN 509 MRD-LE have?
This pistol is equipped with co-witnessing suppressor-height Trijicon 3-dot tritium night sights. These sights are tall enough to be visible over most mounted red dot optics, providing a reliable backup sighting system.
What is the magazine capacity of the FN 509 MRD-LE?
The FN 509 MRD-LE typically comes with two 17-round magazines and one extended 24-round magazine, offering substantial capacity for various applications.
Is the FN 509 MRD-LE suitable for concealed carry?
While it is a duty-sized pistol, some individuals may choose to carry it concealed with the right holster and attire. However, its 4.5-inch barrel and overall dimensions make it larger than typical concealed carry firearms. For more compact options, explore our compact and subcompact handgun selection.
Where can I buy a 9mm semi-auto pistol online?
You can buy a 9mm semi-auto pistol online at Kansas Gunshop (kansas-gunshop.com). We offer a selection of firearms, including the FN 509 MRD-LE, and facilitate FFL transfers.
What is the process for purchasing a firearm online?
When purchasing a firearm online from Kansas Gunshop, you’ll select your desired firearm and proceed to checkout. You will then need to designate a local Federal Firearm License (FFL) dealer in your state where the firearm will be shipped for transfer. Once the firearm arrives at your chosen FFL, you will complete the necessary paperwork and background check according to federal and state laws.
✅ Same-day shipping from Wichita, KS
✅ Discreet packaging
✅ 30-day returns
✅ Secure checkout
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