“Pistol optics are the future.” That’s what we were told during the first few minutes of our meeting with the folks from FN America. Several writers and vloggers had traveled from around the country to get a sneak peek at FN’s newest product intended to be unveiled at the 2020 SHOT show. I had a sneaking suspicion of what it was going to be before I arrived in Pinehurst, N.C. It was only a natural progression, especially with manufacturing and purchasing trends in the shooting industry over the past couple of years.

FN 509 Compact MRD

It turned out that my suspicions were correct, to a degree. Product and PR managers from FN proudly introduced the new 509 Compact MRD. After recently offering the smaller 509 Mid-Size this year, and after reviewing market trends, the company decided to go ahead and flesh out the 509 lineup with a version intended for more discrete concealed carry.

For most folks, the 509 “Compact” would be considered more of a sub-compact pistol with its 3.7-inch barrel and short grip frame that natively houses a 12-round magazine. Oddly enough, despite its intended concealed-carry role, the 509 C MRD seems to have more DNA from the 509 Tactical than it does the 509 Mid-Size. What I hadn’t expected ahead of time was how serious FN was going to get about optics integration with its platform. And that’s where things got pretty interesting.

An Eye to the Future

In its standard configuration, the 509 Compact MRD ships with FN’s Low-Profile Optics Mounting system and a set of suppressor-height sights. While this may seem old hat after the past few years, FN keyed in the small stuff to ensure that its mounting system would be as rugged and durable as possible. With the company’s extensive history in manufacturing hard-use arms for various nations’ militaries around the world, they know what it takes to assemble a system you can bet your life on.

The mounting system includes multiple sets of screws, adapter plates and inserts that the user can configure to mount all of the most popular red dot optics on the market. The system comes with a clearly written and illustrated instruction sheet that details which specific screws, plate and insert are needed for each optic, making installation a breeze.

As part of the low-profile mounting system, FN uses a durable O-ring for resistance while seating and tightening down the optic against the MRD plate and insert. To ensure a tight and secure mount, the company also uses proprietary screws that are sized for the particular optic, include oversized heads to prevent stripping and that use a self-locking thread pitch.

As mentioned, they paid close attention to the details. I’ve seen factory-ready optics systems on pistols that require the user to change out the iron sights to properly co-witness with the optic of their choice. With FN’s low-profile system and the use of inserts of various size and thickness, the user will be able to co-witness the factory suppressor-height sights no matter which red dot optic is employed.

Built Like a Tank

Like its predecessors, everything about the FN 509 Mid-Size looks and feels like a military-grade piece of engineering. In other words, it’s built like a tank. Despite its smaller size, the 509 C MRD has a reassuring, 25.5-ounce heft to it that makes it feel substantial in the hand. Part of that is due to the three types of aggressive and highly effective texturing on the grip that secures the pistol in the hand as tight as a bank vault.

Borrowing from improvements made with the Midsize model, the grip frame includes a Picatinny rail and improved sculpting to provide easier access to the ambidextrous magazine release and to improve user comfort. Another change was in the inclusion of a flatter-faced trigger that improves usability by altering the direction of the press and offering a cleaner break. In addition to the mag release, the pistol also includes an ambidextrous slide catch, sure to make lefties happy.

Up top, the 509 C MRD  includes front and rear cocking serrations on a nicely beveled slide. FN crafted the slide from stainless steel. The black version of the pistol features an FNC (ferritic nitrocarburizing process) finish, as does the cold hammer-forged steel barrel. This treatments provide exceptional corrosion and wear resistance and is ideal for hard use. For those looking for a little color, the 509 C MRD is also available in an FDE version as well.

Other notable features found on the 509 C MRD include a recessed crown to protect the muzzle, an external extractor, a loaded chamber indicator and a polished chamber and feed ramp for reliable feeding. Where allowed, the pistol ships with one 12-round magazine and one extended 15-round magazine. In the occupied states, two 10-round magazines will be shipped instead. The pistol is also compatible with the platform’s 17-round and 24-round magazines with the appropriate grip sleeves.

Dynamic Training

As part of our introduction to the new 509 Compact MRD, FN sponsored an all-day (and night) red dot training class taught by Aaron Cowan of Sage Dynamics. Cowan is an ardent proponent of using red dot optics on pistols. If I remember correctly, he said that he believed in the near future, all newly manufactured pistols would be equipped with red dot optics. His task that day was to help attendees acclimate to quickly presenting and shooting optics-equipped pistols from the draw.

Anyone that has picked up and fired a pistol fitted with a red dot sight knows that it takes some time to get used to “finding the dot” quickly. The pistol must be presented at a different vantage point than when fitted with standard iron sights. That requires the shooter to retrain years of muscle memory to bring the optics-enabled pistol to the correct point each time to quickly acquire the dot and the target.

Before the training started, each person chose and mounted the red dot optic of their choice and there was a wide selection available including Trijicon RMRs and MROs, Leupold DeltaPoint Pros, Aimpoint ACROs and a few others. After getting the pistols zeroed we quickly got into the finer points of drawing and presenting the pistols to quickly acquire the dots and ran various drills throughout the day. Later in the evening, we transitioned to low-light drills in a variety of lighting situations to coordinate the use of the red dot optics with the lights mounted on our weapons. All in all, it was an informative day and the training was very useful and effective.

Rounds Downrange

With around a dozen shooters on the range, I would estimate that we easily went through over 4,000 rounds of range ammunition. During that time, I did not see or hear about a single malfunction with any of the pistols. In fact, I’ve reviewed all of the 509-platform pistols since their introduction and have never encountered a problem of any type. The FNX and FNS pistols I’ve reviewed also ran flawlessly. FN just knows how to produce ultra-reliable weapons.

The reset on the 509 C MRD was very positive. It exhibits a nice tactile pop and audible click when it engaged. It wasn’t the shortest release I’ve experienced, but not the longest either. The trigger also had a fairly crisp break. Meanwhile, the review pistol I received after the class registered a break weight of about 5.25 pounds. The trigger improves upon the first 509 pistol I reviewed. The flatter trigger face helps the shooter deliver more consistently accurate shot placement as well.

That said, there were a couple of minor points I felt could be improved on the pistol’s construction. First, the ambidextrous magazine release is great for left-handed shooters. However, I still experienced the same issue that I did when I tried the other 509 pistols. When engaging the release, the button on the opposite side of the pistol extended into my other fingers. This created a little resistance against the release, slowing down the reload unless I shifted my hand. For this reason, I would much prefer a reversible release instead of an ambidextrous one.

All-Day Shooting

The other thing I noticed could only be picked up on during an extended shooting session. The rounded grip was very comfortable in the hand and the texturing was dang near perfect. But I wish FN incorporated a little more relief cut into the grip behind the triggerguard. During the all-day shooting session, I found the triggerguard rubbed the inside knuckle of the third finger raw during recoil. A little extra room in that area would help with that experience. Although it wouldn’t really be an issue with normal practice or actual use.

Other than these minor points, the 509 Compact MRD handled beautifully and shot extremely well. Since we were shooting offhand, we didn’t do any bench testing. But folks were printing very tight groups throughout the day, especially with the aid of the red dot sights. With its extra heft, the compact shooter soaked up the recoil quite well. It also offered quick follow-ups with its relatively flat recoil impulse.

I liked the ability to switch out to higher capacity magazines. This aided with extra grip area for better control. It also made the 509 Compact MRD a more versatile pistol. For concealed carry, the 12-round magazines help the pistol tuck away discreetly. But the longer 15-round and 17-round magazines allow users to have more rounds on tap. Fitted with the grip sleeves, the higher capacity magazines make the transition seamless. They provide both the look and feel of a larger pistol with all the comfort and advantages that provides.

A New Era

To be honest, during the training that day, I never hit that “Aha!” moment where I found it quicker and more intuitive to get on target with the red dot sight from the draw than with iron sights—especially at closer distances. But, I’m kind of dense that way and it sometimes takes me a while to catch up with things. It’s just going to take continued training to become more proficient and overcome years of doing things the old way.

Even so, I do see the advantages of an optics-enabled pistol. It can enhance the performance of an already incredibly accurate pistol like the 509 C MRD. By offering a platform that can so well leverage the tactical benefits of a weapon light in conjunction with a red dot in such a small, but tough-as-nails, form factor, FN has done a fantastic job for the consumer looking for every advantage in a concealed carry pistol. And when it comes to defending myself or those around me, I’ll take every advantage I can get. For more information, visit

FN 509 Compact MRD Specifications

  • Caliber: 9mm
  • Barrel: 3.7 inches
  • Overall Length 6.8 inches
  • Overall Weight:  25.5 ounces
  • Width: 1.35 inches
  • Grips: Polymer
  • Sights: Suppressor-Height
  • Action: Striker
  • Finish: Ferritic Nitrocarburizing
  • Overall Magazine Capacity: 12/15 (17/24 optional)
  • MSRP: $799

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