Description
The FN 509 Midsize Tactical 9mm 4.5-inch Threaded is a striker-fired, optics-ready pistol that bridges the gap between a full-size duty gun and a compact carry piece. It ships from the factory with suppressor-height night sights and a threaded barrel, so you can run a can right out of the box. This is a multi-role handgun built for shooters who need one platform for competition, home defense, and everyday carry without compromise.
| Manufacturer | FN America |
|---|---|
| Model | 509 Midsize Tactical |
| Material | Polymer frame, stainless steel slide (per manufacturer specs) |
| Compatibility | Accepts all FN 509 magazines; optics-ready for RMR, Holosun, Leupold, and Docter footprint |
| Finish | Black nitride slide, black polymer frame |
| Weight | 26.5 oz unloaded (per manufacturer specs) |
| Condition | New |
Key Features
- Optics-Ready Slide with Low-Profile Mounting System — Why it matters: you can mount a red dot without sending the slide to a machine shop. FN’s system accepts five common footprints, so you aren’t locked into one brand.
- 4.5-inch Threaded Barrel (1/2×28) — Why it matters: the threads are standard pitch, meaning your suppressor or compensator screws on without an adapter. The barrel is cold hammer-forged for longevity.
- Suppressor-Height Night Sights — Why it matters: tritium front and rear let you co-witness with a red dot or shoot in low light. No need to buy aftermarket sights for suppressor use.
- Mid-Size Polymer Frame with 15-Round Capacity — Why it matters: the grip length is shorter than a full-size 509 but longer than a compact, giving you a full firing grip with a 15-round magazine that conceals easier than a 17-rounder.
- FN’s Striker-Fired Trigger with Short Reset — Why it matters: the trigger breaks clean at about 5.5 pounds and resets short, helping you shoot faster without over-travel.
Who It’s For
This pistol is for the shooter who wants one gun that does everything: daily carry, nightstand duty, and range work. It fits shooters who already own a suppressor and want a factory-threaded barrel without the wait. It also suits competition shooters in USPSA Carry Optics division who need an optics-ready slide with a proven track record.
Pros & Cons
- Pro: Factory optics mounting system works with five footprints — no adapter plates required for RMR, Holosun, or Docter.
- Pro: Threaded barrel and suppressor-height sights come standard, saving you $150-plus in aftermarket parts.
- Pro: The mid-size frame balances concealment and capacity — 15 rounds in a grip that isn’t bulky.
- Con: The trigger take-up is a bit long out of the box compared to aftermarket triggers from Timney or Geissele. A few hundred rounds smooths it out, but trigger snobs will want an upgrade.
Comparison
| Feature | FN 509 Midsize Tactical | Zev Technologies OZ9C | Agency Arms AOS Glock 19 |
|---|---|---|---|
| Barrel Length | 4.5 inches (threaded) | 4.0 inches (threaded optional) | 4.0 inches (threaded optional) |
| Capacity | 15+1 | 15+1 | 15+1 |
| Optics Mount | Factory direct (5 footprints) | Factory direct (RMR/Delta Point) | Factory direct (Agency AOS system) |
| MSRP | $929 | $1,199 | $1,895 |
| Best For | Budget-conscious shooter wanting factory threaded barrel + optics | Competition shooter wanting Zev’s steel frame | High-end collector wanting Agency porting and finish |
The FN 509 Midsize Tactical undercuts both competitors on price while delivering a threaded barrel and suppressor-height sights as standard. The Zev OZ9C has a steel frame for less felt recoil, and the Agency AOS gives you custom porting, but you pay double for those features.
FAQ
Does the FN 509 Midsize Tactical come with a threaded barrel?
Yes, it ships with a 4.5-inch cold hammer-forged barrel threaded 1/2×28. You can attach a suppressor or compensator without buying a separate barrel.
What optics fit the FN 509 Midsize Tactical?
The slide uses FN’s low-profile mounting system that accepts RMR, Holosun 407C/507C, Leupold DeltaPoint Pro, Docter/Noblex, and C-More footprints. No adapter plates needed for those patterns.
Is the FN 509 Midsize Tactical good for concealed carry?
Yes. The mid-size frame is 0.5 inches shorter in grip length than a full-size 509, making it easier to conceal while still holding 15 rounds. The threaded barrel adds about 0.5 inches to the slide length, but a good holster handles it.
What magazines does the FN 509 Midsize Tactical use?
It uses FN 509 Midsize 15-round magazines. It also accepts full-size 17-round and 24-round magazines, though they will extend past the grip.
Trust & Delivery
- ✓ Nationwide delivery to all 50 states
- ✓ Ships within 1-2 business days from our FFL
- ✓ 30-day return policy on unfired, unmodified firearms
- ✓ Secure checkout with encrypted payment processing
According to FN America specs, the 509 Midsize Tactical has been on the market since 2019 and has sold over 100,000 units across all 509 variants, making it one of the most proven striker-fired platforms in law enforcement use today.
Last updated: April 2026
Explore more: Semi Auto Handguns | FN Handguns | Optics-Ready Pistols
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