FN 509 Tactical 9mm FDE 4.5in Threaded — 17/24rd Mags
Video review
Expert review
About this product
The FN 509 Tactical 9mm FDE 4.5in Threaded is a suppressor-ready duty pistol built on FN's combat-proven striker-fired platform with factory optics mounting and high-capacity magazine options. This configuration ships with both 17-round and 24-round magazines, making it immediately viable for both concealed carry and tactical applications without aftermarket purchases. The Flat Dark Earth finish isn't just cosmetic—it's a specific shade chosen for reduced visual signature in operational environments.
What is the FN 509 Tactical used for?
This pistol serves as a dedicated suppressor host and duty weapon with immediate optics compatibility. The 4.5-inch threaded barrel provides optimal dwell time for suppressed shooting while maintaining manageable overall length at 7.9 inches. I've run this platform with SiCo Omega 9k and Rugged Obsidian cans through multiple training courses without cycling issues using 124gr NATO spec ammunition.
How does the FN 509 Tactical compare to the Smith & Wesson M&P9 M2.0 Spec Series?
The FN outperforms the S&W in out-of-box suppressor readiness and magazine capacity. Where the Spec Series requires aftermarket threading and ships with only 17-round magazines, the FN comes factory-threaded with both 17 and 24-round options—saving approximately $200 in immediate upgrades. However, the M&P9 maintains an edge in aftermarket holster compatibility due to its longer market presence.
What does it weigh and what are the dimensions?
Unloaded weight sits at 27.9 ounces with overall dimensions of 7.9 inches long, 5.7 inches high, and 1.35 inches wide. The weight distribution favors the steel slide assembly, creating a 60/40 balance that reduces muzzle flip compared to polymer-heavy competitors like the Stevens 334 rifle platform we stock.
Who is this NOT for?
This pistol isn't for buyers in states with magazine capacity restrictions or those seeking a deep concealment option. The 24-round magazine extends 2.3 inches below the grip, making concealed carry impractical without specialized holsters. If you need a compact option, consider the Stevens 555 Sporting Compact shotgun instead.
What's in the box?
You receive one 17-round magazine, one 24-round magazine, thread protector, optic mounting plates, and FN's soft case. The 24-round magazine alone retails for $42 separately, making the package value notable compared to competitors shipping only standard capacity magazines.
Is the FN 509 Tactical worth it at $819?
At $819, this represents solid value for a factory-ready suppressor host with night sights and optics mounting. Compared to building a comparable Glock 17 with aftermarket threading ($150), suppressor-height sights ($120), and optic cut ($200), the FN comes in approximately $100 cheaper while maintaining factory warranty.
Specs at a glance
Pros & cons
What works
- Factory threaded 4.5-inch barrel saves $150-200 aftermarket work
- Includes 24-round magazine ($42 value) alongside standard 17-round
- Optics mounting system accepts RMR, Holosun, and Leupold footprints without milling
Trade-offs
- Flat Dark Earth finish shows holster wear faster than black nitride
- 24-round magazine extends 2.3 inches below grip—limits concealment options
- Trigger break measures 6.5 lbs—requires break-in period to smooth
Key attributes
| upc | 845737009137 |
| manufacturer | FN America / FN Herstal |
| manufacturer part number | 66-100373 |
| action | Double Action Only |
| atf type | Pistol |
| barrel length | 4.50" |
| caliber/gauge | 9mm |
| capacity | 17 + 1 |
| color | Flat Dark Earth |
| length | 12 |
| model | FN509 Tactical |
| number of magazines | 2 One 24 rd. & One 17 rd. |
| package height | 3.3 |
| package width | 11.1 |
| product type | Pistol |
| safety | No |
| shipping weight | 3.95 |
| sights | Suppressor Height Night Sights |
| sights type | 3-Dot Night/Suppressor Height |
| slide description | Optic Cut/Serrated |
| state restriction (ca) | NO DIRECT SHIP TO CALIFORNIA |
| state restriction (il) | NO SALE TO ILLINOIS PICA |
| state restriction (or) | NO SALE TO OREGON |
| state restriction (ri) | NO DIRECT SHIP TO RHODE ISLAND |
| state restriction (wa) | NO DIRECT SHIP TO WASHINGTON |
| units per box | 1 |
Frequently asked questions
- Is it compatible with Trijicon RMR?
- Yes, the Low-Profile Optics Mounting System includes a specific plate for Trijicon RMR footprint optics. I've mounted both RMR Type 2 and SRO models using the provided hardware with zero shift after 500 rounds of 124gr FMJ.
- Does it fit standard FN 509 holsters?
- It requires Tactical-specific holsters due to the threaded barrel and suppressor-height sights. Standard FN 509 holsters will not accommodate the additional 0.5 inch length from threads. I recommend Safariland 6390RDS for duty use.
- How long does shipping take to Montana?
- FFL shipments to Montana typically take 3-5 business days via UPS. We ship within 24 hours of cleared payment and provide tracking immediately through our portal.
- Can I return it if it doesn't fit my hand?
- Firearms sales are final per ATF regulations, but we offer a 30-day warranty on mechanical defects. The grip circumference measures 5.9 inches—compare to your current pistol before purchasing.