Description
The FN 509 Midsize Tactical 9mm 4.5″ Threaded — Matte Black gives you a suppressor-ready, optics-ready duty pistol that doesn’t force you to carry a full-size frame. This is a multi-role semi-automatic 9mm built for everyday carry, home defense, and duty use, with a cold hammer-forged stainless steel barrel threaded 1/2×28 and a slide cut for direct mounting of popular red dots. The midsize frame balances shootability and concealability while still offering a full-hand grip and enhanced ergonomics so you get fast sight acquisition and consistent follow-up shots.
| Manufacturer | FN America (per manufacturer specs) |
|---|---|
| Model | 509 Midsize Tactical |
| Caliber | 9mm |
| Barrel Length | 4.5″ threaded (1/2×28) |
| Material | Cold hammer-forged stainless steel barrel, polymer frame |
| Compatibility | Suppressor, optics, standard FN 509 magazines |
| Finish | Matte black |
| Weight | 26.9 oz (unloaded, per manufacturer) |
| Condition | New |
Key Features
- Optics-Ready Slide — Direct-mount footprint for MRDS without adapter plates, so you can co-witness suppressor-height sights with your dot of choice.
- Threaded Cold Hammer-Forged Barrel — 1/2×28 threads let you run a suppressor or compensator without sacrificing barrel life or accuracy.
- Midsize Frame with Full-Hand Grip — Shorter grip than the full-size 509 Tactical but still gives you a four-finger hold. Conceals easier under a T-shirt while keeping recoil control.
- Enhanced Serrations & Controls — Aggressive front and rear cocking serrations plus an ambidextrous slide stop and reversible magazine release let you run the gun from either side under stress.
- FN Low-Profile Optics Mounting System — Uses a removable rear sight plate so you can install a red dot without losing your backup iron sight. According to FN specs, the system accepts Trijicon RMR, Holosun 407C/507C, and Leupold DeltaPoint Pro.
Who It’s For
This is for the shooter who wants one pistol that pulls triple duty: concealed carry, home defense, and range work. If you plan to run a suppressor for night shooting or competition, you need the threaded barrel. If you want a red dot without sending the slide out for milling, the factory cut saves you time and money. The midsize frame also fits shooters with smaller hands who find full-size grips too thick.
Pros & Cons
- Pro: Out-of-the-box suppressor compatibility with a 4.5″ barrel that stays accurate even after thousands of rounds.
- Pro: Optics cut works with multiple popular dot footprints — no adapter plate needed.
- Pro: Midsize frame is a sweet spot for both concealment and shootability.
- Con: The trigger pull weight is around 5.5–6.5 lbs from the factory — it’s serviceable but not as crisp as a high-end aftermarket trigger. You may want to upgrade if you’re chasing competition splits.
Comparison vs. Competitors
| Feature | FN 509 Midsize Tactical | Zev Technologies OZ9 Compact | Lone Wolf Distributors Alpha Wolf G19 Slide & Barrel |
|---|---|---|---|
| Barrel Length | 4.5″ threaded | 4.02″ threaded | 4.02″ threaded |
| Optic Ready | Factory direct-mount (RMR, Holosun, DPP) | Factory cut for RMR | Aftermarket cut required |
| Frame | Polymer midsize | Polymer/aluminum hybrid | Polymer (Glock gen3) |
| Street Price | $784 | $1,200+ | $450 (slide + barrel) |
| Suppressor Included | No | No | No |
FAQ
Will this accept a standard FN 509 suppressor-height sight?
Yes. The Midsize Tactical uses the same suppressor-height sights as the full-size 509 Tactical. They’re tall enough to co-witness with most red dots mounted directly to the slide.
Can I use my existing 509 holster with the Midsize Tactical?
Most holsters molded for the FN 509 Midsize will fit. The threaded barrel adds about 0.6″ to the muzzle, so check that your holster has an open end or a threaded-barrel channel. The full-size 509 holsters may be too long.
What thread pitch is the barrel?
1/2×28 — the standard 9mm pitch for most pistol suppressors and compensators.
Does this come with a red dot?
No. The slide is optics-ready, but the pistol ships with the factory cover plate installed. You buy the optic separately.
According to the National Shooting Sports Foundation, semi-auto pistols accounted for over 40% of all firearm sales in 2024. The FN 509 Midsize Tactical fits that trend with a suppressor-ready, optics-ready platform at a price that undercuts custom builds.
✓ Nationwide delivery (all 50 states) ✓ Ships 1–2 business days ✓ 30-day returns ✓ Secure checkout
Browse more Semi Auto Handguns and check out our FN Handguns collection for other models.
Last updated: April 2026
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