FN 509 Tactical 9mm FDE 4.5in Threaded — 17/24rd Mags
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Specs at a glance
About this product
The FN 509 Tactical 9mm FDE 4.5in Threaded — 17/24rd Mags is a full-size, striker-fired pistol built on FN's proven 509 platform. It comes ready for a suppressor and red dot right out of the box, with a 4.5-inch cold hammer-forged barrel, suppressor-height night sights, and two magazines.
| Manufacturer | FN America |
|---|---|
| Model | 509 Tactical |
| Caliber | 9mm |
| Barrel Length | 4.5 inches (threaded 1/2x28) |
| Finish | Flat Dark Earth polymer frame, black nitride slide |
| Weight | 26.9 oz (unloaded, per manufacturer specs) |
| Capacity | 17 rounds (flush) + 24 rounds (extended) |
| Sights | Suppressor-height tritium night sights |
| Condition | New |
Key Features
- Threaded barrel with O-ring cap — The 4.5-inch cold hammer-forged stainless barrel is threaded 1/2x28 and includes a locking thread cap with an O-ring. Why it matters: You can mount a suppressor or compensator securely and keep the cap from backing off during live fire.
- Low-profile optics mounting system — FN’s system lets you mount popular miniature red dots like the Trijicon RMR, Leupold DeltaPoint Pro, and Holosun 407C/507C directly to the slide, no milling required. Why it matters: You can switch between irons and a dot without sending the slide to a machine shop.
- Suppressor-height night sights — Three-dot tritium night sights co-witness through most red dots and clear suppressor cans. Why it matters: Your sight picture stays usable whether you’re running a can, a dot, or just the irons.
- Enhanced grip texture — The FDE frame uses FN’s aggressive texture with deep grooves and a high tang. Why it matters: You get a locked-in grip even with sweaty hands or while wearing gloves, and the high tang helps control muzzle rise.
- Two magazines included — Ships with one 17-round flush-fit mag and one 24-round extended mag, plus a soft pistol case. Why it matters: You get a range-ready setup and a backup high-capacity mag for classes or competition.
Who It’s For
This pistol is for the shooter who wants a duty-ready 9mm that can do it all — home defense, range shooting, and suppressed or red-dot use — without needing aftermarket parts. It’s also a solid choice for new gun owners who want one pistol that can grow with them as they add accessories.
Pros & Cons
- Pro: Optics-ready straight from the factory — no slide milling cost or wait.
- Pro: Suppressor-height night sights co-witness with most red dots and clear suppressor cans.
- Con: The aggressive grip texture can be rough on bare skin during all-day concealed carry. A lot of folks wear an undershirt or use a grip sleeve.
How It Stacks Up
| Feature | FN 509 Tactical | Zev Technologies OZ9 | Agency Arms AOS Glock 17 |
|---|---|---|---|
| Barrel length | 4.5" threaded | 4.5" threaded | 4.5" threaded |
| Optics mount | Low-profile system (no plate needed for RMR/DPP) | Zev optics plate system | Agency AOS plate system |
| Magazines included | 2 (17 & 24 rounds) | 2 (17 rounds each) | 3 (17 rounds each) |
| Price | $833.53 | $1,200+ | $1,100+ |
| Frame material | Polymer | Polymer with steel chassis | Polymer |
Frequently Asked Questions
Does the FN 509 Tactical come with a suppressor-height front sight?
Yes. It ships with suppressor-height tritium night sights front and rear. They co-witness with most micro red dots and are tall enough to see over a suppressor.
Can I mount a Holosun 507C directly without a plate?
Yes. The slide has FN’s Low-Profile Optics Mounting System that accepts Holosun 407C/507C, Trijicon RMR, and Leupold DeltaPoint Pro footprints without an adapter plate. You just need the correct screws (included).
What thread pitch is the barrel?
It’s 1/2x28, the standard 9mm thread pitch. Most 9mm suppressors and compensators will fit directly.
Does the 24-round magazine work with other FN 509 models?
Yes. The 24-round extended magazine is compatible with all FN 509 full-size and compact models. It will stick out a bit on the compact frame, but it runs reliably.
Is the trigger the same as the standard FN 509?
Yes, it uses the same striker-fired trigger with a blade safety. Pull weight is around 5.5-6.5 lbs per FN specs. It’s duty-grade — not match-grade, but crisp and repeatable.
Trust & Service
- ✅ Nationwide delivery (all 50 states)
- ✅ Ships in 1-2 business days
- ✅ 30-day return policy
- ✅ Secure checkout
Last updated: April 2026
More options: Semi Auto Handguns | FN Handguns | Suppressor-Ready Pistols