FN 509 Tactical 9mm 4.5in Threaded Barrel 17/24rd Mags
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About this product
The FN 509 Tactical 9mm 4.5in Threaded Barrel 17/24rd Mags is a full-size, optics-ready duty pistol that comes ready to run suppressed right out of the box. Built on FN’s proven 509 platform, this handgun gives you a cold hammer-forged barrel with a 1/2\">-28 thread pattern, suppressor-height night sights, and the Low-Profile Optics Mounting System (LOMS) for direct mounting of miniature red dots. With two magazines (17- and 24-round), interchangeable backstraps, and a 4.5-inch threaded barrel, it's a serious tool for training, competition, or home defense — no gunsmithing required to mount an optic or a suppressor.
| Manufacturer | FN America |
|---|---|
| Model | 509 Tactical |
| Material | Cold hammer-forged stainless steel barrel, polymer frame with steel slide |
| Compatibility | Accepts all FN 509 magazines; optics compatible with Docter/Noblex, Trijicon RMR, Leupold DeltaPoint Pro, and Shield RMS footprints (via included mounting plates) |
| Finish | Black nitride slide, matte black polymer frame |
| Weight | 30.5 oz (unloaded, with magazine) |
| Condition | New |
Key Features
- Cold Hammer-Forged Threaded Barrel — The 4.5-inch barrel is cold hammer-forged from stainless steel and threaded 1/2\">-28. Why it matters: This barrel delivers exceptional accuracy and durability, plus it lets you attach a suppressor or compensator without buying a separate barrel.
- Low-Profile Optics Mounting System (LOMS) — FN’s LOMS allows direct mounting of miniature red dot sights using included plates. Why it matters: You get a co-witness with the suppressor-height night sights, so you can shoot effectively with or without an optic.
- Suppressor-Height Night Sights — Three-dot tritium night sights are tall enough to see over a suppressor and to co-witness with a red dot. Why it matters: Low-light shooting and suppressed use are seamless, no need to swap sights.
- 17- and 24-Round Magazines Included — Comes with one flush-fit 17-round and one extended 24-round magazine. Why it matters: You get a standard carry capacity and a high-capacity option for training or competition — no extra purchase needed.
- Interchangeable Backstraps — Four different backstraps let you adjust grip circumference. Why it matters: Shooters with small or large hands can dial in the fit for better recoil control and accuracy.
Who It's For
This pistol is built for the shooter who wants one gun that can do it all: duty carry, range training, suppressed shooting, and red dot use. If you’re a new shooter looking to start with a serious tool that you won’t outgrow, or a veteran shooter who wants a factory-ready suppressor host with optics compatibility, the FN 509 Tactical delivers without requiring aftermarket parts. It’s also a solid choice for law enforcement or military personnel who want a familiar platform with modern features.
Pros & Cons
- Pro: Optics-ready out of the box with multiple plate options — no milling needed.
- Pro: Threaded barrel is standard, not an add-on, saving you $150–$200 compared to buying a separate barrel.
- Pro: Two magazine capacities give flexibility for carry (17) or training (24).
- Con: The trigger, while serviceable, has a slightly longer reset than aftermarket triggers from Geissele or Timney. Some shooters may want to upgrade it for competition use.
Comparison
| Feature | FN 509 Tactical | Zev Technologies OZ9 | Agency Arms AOS G17 |
|---|---|---|---|
| Barrel Length | 4.5\" threaded | 4.5\" threaded | 4.49\" threaded |
| Optic Mount | LOMS (multiple footprints) | Zev RMR-cut slide | Agency AOS system |
| Magazine Capacity | 17/24 rounds | 17/21 rounds | 17/24 rounds |
| Price | $833.53 | $1,499.00 | $1,695.00 |
| Night Sights | Suppressor-height tritium | Suppressor-height tritium | Suppressor-height tritium |
| Grip Adjustment | 4 backstraps | Modular grip frame | 3 backstraps |
FAQ
Does the FN 509 Tactical come with suppressor-height sights?
Yes, it comes standard with suppressor-height three-dot tritium night sights. These are tall enough to co-witness with most miniature red dot sights and to see over a suppressor.
What optics are compatible with the FN 509 Tactical?
According to FN specs, the Low-Profile Optics Mounting System includes plates for Docter/Noblex, Trijicon RMR, Leupold DeltaPoint Pro, and Shield RMS footprints. You can mount most popular red dots without any adapter or milling.
Is the barrel on the FN 509 Tactical threaded?
Yes, the 4.5-inch cold hammer-forged barrel is threaded 1/2\">-28, which is the standard thread pitch for 9mm suppressors and compensators. A thread protector is included.
What magazines come with the FN 509 Tactical?
It ships with two magazines: one 17-round flush-fit magazine and one 24-round extended magazine. Both are compatible with all FN 509 models.
Delivery & Support
- ✔ Nationwide delivery (all 50 states)
- ✔ Ships 1-2 business days
- ✔ 30-day returns
- ✔ Secure checkout
Explore more handguns in our Semi Auto Handguns collection, or check out Optics and Suppressors to complete your setup.
Last updated: April 2026