FN America took their line of striker-fired pistols in a new direction in 2017 with the introduction of the FN 509. It was born out of their entry in the Army’s modular handgun system competition. They said at the time that the 509 had more than 1 million rounds to ensure that their new flagship 9mm pistol was reliable.
All of which is a long way of saying that if you want a good evaluation of the FN 509 Midsize 9mm pistol, read our reviews of the original full-size and tactical models of the gun. Everything we’ve had to say about the previous models goes for the new FN 509 Midsize.
The big difference: about .36 of an inch. That’s the amount FN chopped off of the FN Midsize’s handle. It may not sound like much, but it makes a significant difference in your ability to conceal the gun. Both the Midsize and the big boy models have the same stainless steel four-inch barrel length, same sight radius.
Rather than a plastic clamshell box, the more compact pistol comes in a nicely embroidered zippered soft case. FN throws in a second flatter backstrap for small-handed shooters like me along with two 15-round magazines. Be forewarned, you’ll need a long punch to change it out yourself. It’s a PITA, but a minor gripe as you’ll only have to do this once.
The 509 Midsize has bevels cut in at the bottom of its multi-surfaced grip to help you yank out a magazine should one fail to eject. That never happened to us, but it’s definite a plus.
Like the earlier models, the Midsize’s grip is a cavalcade of textures; pyramidal nubs on the sides, angled “tabs” on the front and back and skateboard tape-like surfaces on the areas above where your thumb naturally falls.
Some have complained about this in terms of aesthetics, but as a practical matter, it work very well. Your hold on the gun will be sure and firm (even with a wet hand) without the texture being too aggressive.
Like their FNS pistols, the 509s have an elongated magazine release button. Unlike those earlier models, the 509’s buttons are more textured and stand a little more proud of the grip, resting in contoured “pocket.” That pocket has been re-shaped slightly (it’s a little larger) from that of the full-size gun, making for easier activation by small-handed shooters without changing their grip.
Sure to please lefties, the 509 Midsized is full ambidextrous right out of the box. There are slide stop levers on the left and right sides and you won’t have to switch the magazine release.
The 509’s stock trigger is very good. It breaks cleanly at 5.4 lbs and has a very tactile, audible reset. Controlled rapid fire and double-taps are not an issue. FN says the 509 Midsize trigger shoe has a flatter face than earlier models making for a better, more controlled trigger press. Jeremy wasn’t in love with the earlier version on the Tactical model. This one is near-ideal.
Takedown is as simple as a striker-fired gun should be. Check that the pistol is clear and safe. Then lock the slide back, drop the take-down lever, release the slide forward, then pull the trigger. The slide comes right off.
That captured recoil spring on the 509 Midsize is the same one FN included in the 509 Tactical model. With its cocking serrations fore and aft, the lighter spring makes the 509 Midsize easier to rack, but the pistol still performed flawlessly with a variety of ammo weights we tested.
The 509 Midsize has drift-adjustable, glow-in-the-dark three-dot luminescent sights (tritium night sights are available). The front of the rear sight is vertical, so you can use it to rack the matte black slide one-handed on a belt or hard surface if the need arises. And we hope it doesn’t.
We tested the new Midsize with a range of range ammo from Armscor (115 and 147 grain), Winchester and Remington. Personal defense ammo tested included Federal HST and Remington HTP.
Braced groups at 25 yards ranged from 4.15 (Federal HST) to just over 5.5 inches (Winchester white box). Those are very respectable results that indicate — as if there were any doubt — that the 509 Midsize is more than accurate enough at personal defense distances, either while carried or in a home defense role.
The 509 Midsize will, of course, most often be compared to the GLOCK 19 Gen5 which is also an excellent gun. The FN costs anywhere from $25 to $60 less, has better ergonomics and a better trigger. Then again, the 509 has fewer aftermarket choices, though there are more available all the time. You owe it to yourself to shoot both.
Specifications: FN 509 Midsize Pistol
Magazine Capacity: 10 or 15 Rd (higher capacity mags can be used with a grip sleeve)
Weight: 26.5 oz.
Barrel Length: 4.0″ cold hammer forged
Overall Length: 7.4″
Trigger Pull: 5.5 – 7.5 lb.
MSRP: $649 (about $549 retail)
Ratings (out of five stars):
Aesthetics: * * * *
Is it beautiful? No 9mm striker-fired pistol is beautiful. But it definitely isn’t ugly in the way some are. The 509 Midsize has a certain industrial style to it.
Reliability: * * * * *
Pefect. Nothing else to say.
Ergonomics: * * * * *
The 509 Midsize does every little thing right. It’s fully ambidextrous to accommodate lefty shooters. The texturing is an effective mix of just the right patterns in just the right places. The mag release and replaceable slim backstrap mean even those of us with small hands can reach all the controls. The external extractor acts as a loaded chamber indicator. If only every pistol maker put this much thought into their designs.
Customization: * * *
As good as FN pistols are and always have been, they’re not up there in sales volume with the GLOCKs, Smith & Wessons, SIG Sauers and Rugers of the world. That’s a shame, because they consistently match or beat the other big gun makers’ products. That means, however, that there are fewer options out there for holsters, sights, replacement triggers, etc. Which isn’t to say there are none. You can find everything you need and there are more offered all the time.
Overall: * * * * *
The 509 Midsize is an excellent 9mm pistol. It’s almost the Goldilocks of gun sizes…just right for almost any job short of pocket carry. If you’re going to own one handgun — for carry, for home-defense, for competition, for fun — there are a lot of good arguments for making this that gun.