Description
The FN 509 Midsize MRD Handgun 9mm Luger 10rd Magazines (2) 4″ Barrel FDE NMS is the concealed carry evolution you’ve been waiting for. This factory-ready optics platform gives you direct mounting for over 10 different miniature red dot sights without needing a gunsmith. It’s built for the guy who wants a reliable, shootable carry gun that keeps up with modern EDC demands.
| Manufacturer | FN America |
|---|---|
| Model | 509 Midsize MRD |
| Material | Stainless steel barrel, polymer frame |
| Compatibility | FN 509 full-size magazines (with sleeve), most MRD optics (RMR, Holosun, etc.) |
| Finish | Flat Dark Earth (FDE) NMS |
| Weight | 26.1 oz (unloaded, per manufacturer specs) |
| Condition | New |
Key Features
- FN Low Profile Optics Mounting System — Why it matters: Direct-mount your favorite red dot without adapter plates, keeping the slide profile low and snag-free for daily carry.
- 4-Inch Barrel with Midsize Frame — Why it matters: Balances concealability with a longer sight radius for faster, more accurate shots. It’s the Goldilocks size for EDC.
- Improved Textured Backstraps — Why it matters: Two included backstraps with aggressive texture give you a secure grip in wet or sweaty conditions, so the gun stays planted during recoil.
- Ambidextrous Slide Stop and Magazine Release — Why it matters: Left-handed or right, you get the same manipulation speed. No training scars for southpaws.
- 10-Round Magazines (2) — Why it matters: Compliant in restricted states, but compatible with larger FN 509 mags when you want extra capacity. Use the included sleeve for a full-size grip.
Who It’s For
This pistol is for the daily carrier who’s made the switch to red dot sights and wants a factory-supported platform. It’s for the guy who values reliability over gimmicks and needs a gun that works out of the box with his existing holster and gear. If you’re running a RMR or Holosun on your carry gun, the FN 509 Midsize MRD is your next upgrade.
Pros & Cons
- Pro: Direct optic mounting for 10+ MRD footprints — no plate hassle, no added height.
- Pro: FN reliability pedigree; this gun runs with duty-grade durability.
- Pro: FDE finish is durable and matches popular EDC aesthetics.
- Con: Trigger is serviceable but not match-grade; aftermarket upgrades exist if you want a lighter pull.
Comparison: FN 509 Midsize MRD vs. Zev Technologies OZ9 vs. Agency Arms Syndicate
| Feature | FN 509 Midsize MRD | Zev Technologies OZ9 | Agency Arms Syndicate |
|---|---|---|---|
| Price | $705.34 | $1,200+ | $2,500+ |
| Optic Mount | Direct mount (10+ optics) | Direct mount (RMR/Holosun) | Direct mount (RMR/Holosun) |
| Frame | Polymer, interchangeable backstraps | Polymer/aluminum hybrid | Polymer/aluminum hybrid |
| Barrel Length | 4″ | 4.17″ | 4.17″ |
| Weight | 26.1 oz | 25.6 oz | 26.5 oz |
| Best For | Budget-conscious EDC with factory reliability | Competition or premium build | Custom shop level with high investment |
FAQ
Does the FN 509 Midsize MRD come with optics mounting plates?
Yes, the FN Low Profile Optics Mounting System uses a direct-mount design. The pistol includes the necessary spacers and screws to mount most miniature red dot sights (RMR, Holosun 407C/507C, etc.) without aftermarket plates. Check the included manual for your specific optic’s screw pattern.
What holsters fit the FN 509 Midsize MRD?
Most holsters made for the standard FN 509 Midsize will fit this MRD version, but you’ll need an optic-cut holster to accommodate the red dot. Brands like Tier 1 Concealed, Vedder, and Bravo Concealment offer models specifically for the 509 Midsize MRD. Confirm barrel length (4″) when ordering.
Can I use full-size FN 509 magazines in this pistol?
Yes, the FN 509 Midsize MRD is compatible with larger FN 509 magazines (15, 17, 24 rounds). Use the included magazine sleeve to fill the gap between the mag and the grip for a full-size feel. The factory 10-rounders are included for restricted states.
Is the FDE finish durable for daily carry?
According to FN specs, the FDE NMS finish is a corrosion-resistant coating applied to the slide and barrel. It holds up well to holster wear and sweat, though like any finish, it may show holster wear over time. It’s not as hard as DLC but is more durable than standard bluing.
What’s the trigger pull weight on the FN 509 Midsize MRD?
The factory trigger pull is approximately 5.5 to 6.5 lbs, per manufacturer specs. It has a distinct wall and a short reset. Some shooters find it heavier than preferred, but it’s consistent and safe for carry. Aftermarket triggers from Apex or Overwatch Precision are available if you want a lighter pull.
Ready to Upgrade Your EDC?
✓ Nationwide delivery (all 50 states) — ships to your FFL
✓ Ships 1-2 business days from order confirmation
✓ 30-day returns — no restocking fee if unfired
✓ Secure checkout with encrypted payment processing
Browse more in our Semi Auto Handguns or Concealed Carry categories. Also check out Optics & Red Dots to pair with this MRD-ready pistol.
Last updated: April 2026
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