# FN 509 MRD - 9mm Tactical Pistol with Fiber Optic Sights

**Brand:** FN Herstal
**Category:** Full Size Handguns
**Caliber:** 9mm

## Specifications

- **Caliber:** 9mm
- **Barrel Length:** 4"
- **Capacity:** 10 rounds
- **Weight:** 28 oz
- **Overall Length:** 7.4"
- **UPC:** 845737016906
- **SKU:** UCEt9uKhW

## Description

The FN 509 MRD FOS is a 9mm Luger semi-automatic pistol with a 4-inch cold hammer forged barrel, polymer frame, and stainless steel slide in black PVD. It ships with five magazines and weighs 28 oz. The double-action-only trigger has a flat face that keeps the pull geometry consistent shot to shot.

### Key Specifications
- **Manufacturer:** FN
- **Model:** 509 MRD FOS
- **Caliber:** 9mm Luger
- **Barrel Length:** 4 inches
- **Capacity:** 10+1 rounds
- **Weight:** 28 oz
- **Frame Material:** Polymer
- **Slide Material:** Stainless Steel (Black PVD finish)
- **Grips:** Black Textured with Interchangeable Backstrap
- **Sight Configuration:** Steel Co-Witness / Front Fiber Optic
- **Overall Length:** 7.40 inches
- **Action Type:** Double Action Only (DAO)
- **Condition:** New in Box

The ACRO mounting plate is already installed, so adding a micro red dot requires no machining. The front fiber optic sight co-witnesses with the steel rear, which works well in varied lighting. Interchangeable backstraps let you dial in the grip fit without aftermarket work. Five magazines in the box is a genuinely useful inclusion.

## What Reviewers Say

*Quoted verbatim from YouTube reviews. Each link opens the video at the moment quoted.*

> I think this gun is largely underrated underrated in a very very criminal way.
>
> — [Colion Noir](https://www.youtube.com/watch?v=ZTOrm-lH0ck&t=77s)

> This trigger is good so as you see here there's no stacky grittiness right here it's smooth.
>
> — [Colion Noir](https://www.youtube.com/watch?v=ZTOrm-lH0ck&t=574s)

> I feel more confident with a bigger gun in my hand if I'm in a situation where I may find myself in danger.
>
> — [Colion Noir](https://www.youtube.com/watch?v=ZTOrm-lH0ck&t=358s)

> These are my favorite suppressor height sights if I could put these suppressor he sights on every gun I absolutely would.
>
> — [Colion Noir](https://www.youtube.com/watch?v=ZTOrm-lH0ck&t=742s)

## What Customers Say

*AI-generated insights from customer reviews*

The FN 509 MRD has a good reputation for reliability and consistent accuracy. Recoil is manageable and the action runs smoothly across a range of 9mm loads. Most owners report no significant reliability issues.

Ergonomics come up frequently as a positive - the grip texture and adjustable backstraps give most hand sizes a solid purchase, which helps with control during faster strings.

The fiber optic front sight gets mentioned often. It picks up light well in most conditions and speeds target acquisition. Some shooters swap it for a different setup based on personal preference, but it's a functional starting point.

The MRD optics-ready mounting is a clear draw for anyone planning to run a micro red dot. The ability to mount directly without a gunsmith is genuinely useful.

Price is the main point of debate. The 509 sits in a competitive segment, and a few buyers question whether it does enough to justify the premium over alternatives. Those who prioritize the optics-ready platform and cold hammer forged barrel tend to find the cost reasonable.

## Pricing

**1 offers available**

| Vendor | Price |
|--------|-------|
| Guns Com | $829.99 |

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*Data from [GunsNation](https://gunsnation.com)*