Gun Review: FN 509 LS Edge Long Slide 9mm Pistol

FN 509 LS Edge Long Slide 9mm Pistol

FN 509 Edge (image courtesy JWT for

FN Herstal developed the FN 509 pistol to win the US Army and Air Force’s Modular Handgun System competition. That didn’t happen.

I won. You won. We all won. Because the result of that competition was a drive to create a family of polymer framed striker fired pistols that have proven to be some of the best in their class. And that family just got a little bigger. Bigger. Faster. And prettier.

Kicking off what FN promises to be a new line of premier versions of their existing firearms, FN has just released a full-framed long slide version of their popular duty pistol, the 509 LS Edge.

FN 509 LS Edge Long Slide 9mm Pistol

(image courtesy JWT for

The most obvious change over the previous FN 509, 509 Midsize, Compact, and Tactical pistols is the 509 LS Edge’s slide. Take a look at it. That’s a 6.7″ sight radius, just a bit longer than the standard 1911 Government. All that real estate helps with precise shooting, and the length and slightly more weight at the front end helps keep the sight returning quickly to the target for fast follow-ups.

FN 509 LS Edge Long Slide 9mm Pistol

(image courtesy JWT for

It’s also got a good bit of styling. Marketing for any pistol with slide cuts on the frame says that they are there to improve slide speed and the recoil profile. I don’t buy it, and I’d rather have the weight to keep the muzzle down. They’re there to look cool, and on the 509 LS Edge, it does look cool.

FN 509 LS Edge Long Slide 9mm Pistol

(image courtesy JWT for

But just forward of those cuts is what’s really worth paying attention to. Take a look at that ball end mill cut. Does that remind you of any other pistol? It should. That’s the slide cut synonymous with the Browning Hi-Power that was produced by FN as well.

That mill cut provides an elegant transition to the muzzle end of a flat sided slide, the primary reason for its inclusion on most custom 1911s. On the 509 LS Edge, it’s aesthetically pleasing, but it’s also a nod to FN’s heritage and makes gun nerds smile. (Ask me how I know.)

FN 509 LS Edge Long Slide 9mm Pistol

(image courtesy JWT for

The whole slide is well-finished with ultra slick and ultra-durable graphite physical vapor deposition (PVD).

FN guns come in two colors; grey and every shade of brown on earth. This one is grey and very well done. FN raised the bar on “standard” for their finish on the current US Army service rifle, and they did so again here. This is the kind of finish customers are used to paying a pretty penny for, and it’s worth every one of those pennies.

FN 509 LS Edge Long Slide 9mm Pistol

(image courtesy JWT for

The 509 LS Edge’s polymer frame is textured on every side, in a couple of different styles. The front and rear of the grip have heavy raised bars while the sides are stippled like skateboard tape, and also features the FN logo.

The backstrap is removable. Both a larger, more rounded version and a flatter, thinner version are included. TTAG’s editor Dan liked the smaller backstrap, but the larger version was necessary to get my hand in the right position for the trigger.

FN 509 LS Edge Long Slide 9mm Pistol

(image courtesy JWT for

The frame continues with all of the things we’d find on a race gun, but turned down to 8. That is, all the features are there, they’re just not obnoxiously there.

FN 509 LS Edge Long Slide 9mm Pistol

Courtesy FN

For example, the extended and flared magazine well. It’s effective at quickly funneling the magazine into the gun, but it’s not overly large and won’t get in the way of duty gear or other everyday wear clothing.

FN 509 LS Edge Long Slide 9mm Pistol

(image courtesy JWT for

The only thing I don’t like about the frame is where it terminates into the magazine well. There are small divots at the bottom of the polymer portion of the grip. Those divots serve a purpose. In the event of a stuck magazine, the divots allow the user to grip the magazine base to rip the mag out of the gun.

The 509 LS Edge’s removable magazine well now sits below those divots, making them not only useless, but inhibit the ability for the shooter to rip out a mag.

That said, the fastest way I’ve found to get a stuck magazine loose is to simply hold the mag release down, take a quick knee, and slam the trigger guard against your thigh. If you didn’t bruise your leg, you probably didn’t hit it hard enough. I’ve yet to find a mag that wouldn’t drop using this method. You may end up with some rounds spilled out, but it gets the rest of the magazine, or hopefully your spare, back in the gun quickly.

FN 509 LS Edge Long Slide 9mm Pistol

(image courtesy JWT for

For the 509 LS Edge, that magazine release you’ll be holding is well raised, oblong, and nicely textured. Again, it’s easy to get to, hard to miss, but not so large that shooters with large hands or those wearing gloves should expect to inadvertently hit it.

The trigger guard is undercut and even with the very high grip this affords my size large hand, it puts my middle finger positioned just under the magazine release, right where it should be.

FN 509 LS Edge Long Slide 9mm Pistol

(image courtesy JWT for

Finally, the front of the frame sports a full four slot Picatinny rail for mounting your chainsaw bayonet or weapon light.

I’m rarely a fan of the triggers on striker fired guns, and this one is no exception. It’s without a doubt an improvement over the trigger on the already pretty good stock gun. On my Lyman digital trigger scale, this one broke at 4lbs 9.6oz, as an average over 5 trigger pulls. It’s also very consistent, with just over one ounce as the difference between the heaviest and lightest of those pulls. That’s outstanding.

The reset is good as well…very short, clean and quick to get back to. The Edge sports a wide, flat trigger shoe that breaks right at 90 degrees. All of that combined makes for very fast, precise follow-up shots. Here, the trigger stands out as equal or better than anything else on the market, including the aftermarket striker-fired gun triggers.

FN 509 LS Edge Long Slide 9mm Pistol

(image courtesy JWT for

What doesn’t impress me about the trigger is the initial pull. There are 3 separate and distinct stops prior to the trigger shoe hitting vertical and the striker release. The result is a kind of light staccato mush, and detracts from the otherwise stellar performance.

There were no surprises at all when it came to the precision the 509 LS Edge is capable of. Beyond the optics mount, the stock iron sights setup is as perfect as it gets. There is zero reason to swap the sights on this gun. Whatever you’d buy probably isn’t this good. The front sight is a 1mm thick green fiber optic drift-adjustable front post.

FN 509 LS Edge Long Slide 9mm Pistol

(image courtesy JWT for

The rear sight is a little more interesting. The sight itself is tall, with a flat back rear face and serrations at the bottom. When the front sight is in the middle, it splits the sight picture into three equal parts. There’s also a bit of an optical illusion that makes the rear sight look like it’s a U-shaped notch when the front sight is centered, because the bottom edges of the rear are angled inward and not straight down.

The overall effect is that the sight lines up very quickly on target, and it’s just perfect to get a bright center dot at a 6 o’clock hold.

FN 509 LS Edge Long Slide 9mm Pistol

Dan Z. for TTAG

Without an optic installed, the stock iron sight plate rises in the rear to form protective ears on either side of the rear sight. As an added bonus, it give the shooter lots of real estate to grab a pocket, belt, boot, whatever is available to quickly rack the gun in the event the shooter needs to fix a malfunction with a single hand.

FN 509 LS Edge Long Slide 9mm Pistol

The FN 509 LS Edge also features FN’s patented Low-Profile Optics Mounting System and includes multiple plates and mounting hardware. I’ve struggled to get on the miniaturized red dot optic (MRO) train. Most of that is because I’ve just not trained enough with it, and I’m always looking for the dot.

That training time is dramatically reduced here. I don’t fully understand why, but with this gun, and a Leupold DeltaPoint Pro mounted, the red dot lines up right with the front sight as I press forward, as it should.

Maybe it’s because the co-witnessed irons are high, and the MRO mounts so low. Whatever the reason, it works better for me than any other pistol optics system I’ve used, and makes me reconsider dedicating more time to an MRO to put on a carry gun.

FN 509 LS Edge Long Slide 9mm Pistol

(image courtesy JWT for

There’s really no disadvantage to an MRO that co-witness with the stock irons. If the technology fails, the iron sights on the gun are still there. You have a redundant sight system that’s now more reliable than simple irons. Two is one.

It’s also better for most folks when shooting far away. Shooting a plate rack at 100 yards is much easier with an MRO than even with the best of iron sights. But that’s not the biggest advantage, in my rarely humble opinion.

FN has had MROs on their guns for a while, and I’ve tried them since they came out. I’ve run one on my FNX-45 Tactical when hunting pigs at night for years.

This, for me, is the huge advantage of MROs. It’s not shooting 8-inch targets at 7 yards in the daylight, or plates at rifle ranges. It’s shooting anything at night. With a modern MRO, you’re running the exact same sight picture in daylight, low light, or with NVGs in no-light situations. The advantage of this feature can not be overstated.

FN 509 LS Edge Long Slide 9mm Pistol

(image courtesy JWT for

On the range, the 509 LS Edge performed as reliably as one would expect from a manufacturer who can rightly claim to be “the world’s most battle proven firearms.” This pistol now has over 700 rounds through it. The first 600+ were 115gr FMJ. Zero surprise that it ran there.

I also threw in my trademarked (not actually trademarked) “box of loosies” at it. This is simply the bag of random leftovers I have when I only have one or two of any particular brand left in the box. I ran 100 rounds like that. These included IMI’s weird die-cut round, as well as defense rounds from Remington, Winchester, Wilson Combat, and a few I didn’t recognize anymore.

Weights ranged from 100gr frangible to 147gr FMJ and HP, and even some 165s. After all this, I shot groups. I never cleaned or lubed the gun, other than my initial lubrication with a few drops of Lucas oil, until it was time for photos.

At no time did I experience any issues loading, firing, or ejecting. None of the three 17-round supplied FN magazines ever failed to lock into the gun with a light push. None ever fell out. None failed to feed.  The firearm never failed to lock back on an empty magazine. I attempted to induce a malfunction by limp-wristing the gun, as well as holding it at awkward angles. The 509 LS Edge never made so much as a hiccup.

FN 509 LS Edge Long Slide 9mm Pistol

It’s also capable of better-than-acceptable precision with a fairly wide range of ammunition. The worst performing round (and that’s surprising because it’s usually one of the best) was IWI’s 115gr die cut bullet, printing 2″ five round groups at 25 yards, averaged over four shot strings. Again, that was the worst.

The best was Winchester’s 124gr +P PDX1 JHP, printing 1.5″. This is a great-shooting round in every gun I use, with a terminal ballistic performance to match. Those rounds bracketed the others I put through the gun, and are the results shooting the gun with the supplied iron sights.

Interestingly enough, with the DeltaPoint Pro installed, the same results occurred, with only a .2″ improvement with the Winchester cartridge and identical performance with the IWI round.

FN 509 LS Edge Long Slide 9mm Pistol

(image courtesy JWT for

This pistol is accurate and reliable, but it’s also just fun to shoot. Everybody loves shooting a full-frame 5-inch barreled 9x19mm. It feels like cheating. Recoil is very minimal, allowing new shooters to get comfortable behind the gun, or experienced shooters to really push themselves.

FN 509 LS Edge Long Slide 9mm Pistol

Courtesy FN

The long slide, full grip, and narrowed front end allow for fast starts and stops on the gun, making for reduced time and improving accuracy during target transitions. Given today’s ammunition prices, you’ll likely run out of ammunition long before you tire of shooting the 509 LS Edge.

When it comes to new products, FN Herstal is sort of an odd duck. The same company that waited until the year 2000 to produce a striker-fired polymer frame 9x19mm, only to replace it five years later with a hammer fired gun, is the same company to produce the innovative P90, Five-Seven pistol, and 5.7x28MM ammunition.

The striker-fired FNS pistol didn’t come out until 2011, but by 2015, you could get the first production optics-ready pistol on the market, the hammer fired FNX-45 Tactical.

FN 509 LS Edge Long Slide 9mm Pistol

Courtesy FN

FN is once again behind the competition when it comes to timing, but again, still ahead of the competition when it comes to execution. I’ve shot the heck out of guns that blur the lines between duty and competition from GLOCK, SIG, and others, and this one is the best I’ve seen of the striker fired lot.  It handles well and shoots well, but it’s the perfection of the optic system that nudges it to the front of the line of those guns.

I don’t know what the next gun will be in the Edge line, (I’m hoping a suppressor- and MRO-ready FN Five-seveN), but if the rest of them are anything like this one, I suspect FN will have a whole lot of hits on their hands.

FN 509 LS Edge Long Slide 9mm Pistol

(image courtesy JWT for

The 509 LS Edge made me rethink MROs and switch my opinion on how easy the transfer to that superior optics system really can be. Plus, it’s a whole lot of fun to shoot.

Specifications: FN 509 LS Edge

Caliber: 9mm
Capacity: 17+1
Action: Double-action, striker fired
Barrel Length: 5 inches
Overall Length: 8.2 inches
Width: 1.35 inches
Height: 5.9 inches
Weight: 31 oz.
Magazines: 3 included
MSRP $1,499 (about ($1300 retail)

Ratings (out of five stars):

Style and Appearance * * * * *
For the class it’s in — polymer-frame striker fired handguns — the 509 LS Edge has a lot going for it.  That’s a relatively low bar, but they bested it handily.

Customization * * * *
An easy backstrap change is now standard, and not having a threaded barrel is a disappointment that I hope FN quickly rectifies. The wide range of optic mounting hardware right from the factory is a big plus.

Reliability * * * * *

Precision * * * *
Very good, but none of the rounds hit or broke the 1″ at 25 yards mark I’d consider a requirement for five stars from a firearm of this size.

Overall * * * * 1/2
With a less-than-perfect trigger, the mistake of not altering the magazine well or the grip to accommodate a stuck magazine, and no threaded barrel, the 509 LS Edge doesn’t garner all five stars.  But man, it only misses by a little. The sighting system, both irons and MRO, is by far the best in class. So is the pistol’s finish. The controls are great. The trigger is as good as anything else out there. The case it comes with, as well as the three standard magazines are added bonuses. The 509 LS Edge is a strong opening for FN’s new Edge line and a great option for the professional or aspiring shooter who wants the very best of this class of firearm.


  1. avatar kahlil says:

    another plastic frame and striker-fired wonder 9. wow. When they come out with something truly revolutionary or game changing it would be worth looking at.

    1. avatar Montana Actual says:

      I’ll never understand how some people don’t consider a new gun “interesting” because of the components used to make it. If you like all metal things, fine. But expecting outdated designs that cost more to make to be more innovative and more interesting or “game changing” maybe you are looking into the wrong industry.

      1. avatar kahlil says:

        The FK Brno (PSD I think) gun is another $1000+ polymer wonder but has more added value and interesting features. Overpriced, certainly, but far less than the steel framed $7500 field gun. The Laugo Alien is another I have my eye on and hope to acquire but the going rate (if it is currently available) is out of my expense range. The PS50 is also an example of thinking outside the box and bringing something creative to the table.

        Another striker-fired plastic framed at an obscene price is just, meh. Not everything has to be steel and wood (though that is ideal in my humble opinion, I do carry a Px4 Compact so I have made a compromise) but if the only real innovation or trend is to slap an optics mount and call it done we don’t have much more to aim for. You have your opinion and I have mine. If you’re going to toss all that cash towards a firearm why plastic? Does not compute.

    2. avatar possum says:

      If I had a Wife and I bought a polymer framed gunm for a thousand bucks,,. ,,,,, hard telling but it wouldn’t be pretty.

      1. avatar Idaho Boy says:

        So why not buy a pretty gun for that much money? Just tell your wife she’s pretty too.

  2. avatar NTexas says:


  3. avatar Idaho Boy says:

    When I compared pictures of the frame of this weapon to the base model, they look identical to me, right down to the divots. Unless I am mistaken about that, they are probably using the exact same frame to keep the “One Frame to Rule Them All” motif going.

    Or maybe to save a little coin. Or both.

  4. avatar Specialist38 says:

    Nice review.

    Out of what I’d want to spend as I don’t care about the optics plate.

    Glad to see companies are trying to make polymer a little more precise.

  5. avatar LcinCO says:

    So a Canik TP9SFX, but at 3x the cost. Or a Glock 34 at 2.5x the cost. This is worth $700 street, not $1300.

  6. avatar Idaho Boy says:

    Might be closer to 2x the cost for a Glock 34 Gen 5 MOS.

    But that’s still one in each hand.

    Suppressive fire!

  7. avatar GS650G says:

    Rather have a PPQ steel frame for that money. Q Match version.

  8. avatar Montana Actual says:

    Damn this thing is sexy.

    No new things for this guy though. Except ammo. I have been buying ammo I don’t even need just to use for bartering once our currency fails.

    1. avatar Idaho Boy says:

      Assuming you are correct, I wouldn’t stock up on ammo for bartering. Whiskey is widely available right now, and lots of folks are going to need a stiff drink in the End Times.

      Of course, you could always stock up on weed as well for the teetotalers.

  9. avatar Debbie W. says:

    I’ve never owned an out of the box firearm that did not have some kind of warts. I prefer reviews where the firearm has been set up and then taken to the range. I don’t want to hear how the trigger feels gritty but might improve after 500 rounds, etc.
    Speaking of warts I purchased a pistol grip Citadel Warthog 12 ga semi. It is not an out of the box go to range shotgun. However if you like saving money and know how to make ’em run then you’ll really like this home defense shotgun. After the tweaks are done all it needs is an 1/8″ thick cheek-ezz and a shell holder. Legacy Sports has a disassembly, reassembly video.

    1. avatar possum says:

      So what did you have to do to make it work the way you wanted it to work? Would it work okay out of the box?.

      1. avatar Debbie W. says:

        Well possum prior to purchase you begin by watching the video. From there you open the box and check ease of operation and 99% of the time it is not smooth, etc. Next you apply all your hard learned tweaking experience to said firearm and if done right it spits projectiles like there is no tomorrow. If it does not perform you take it apart and start all over until it meets your standards. Your standards may not be as high as mine. Most of the time tweaks involve various grades of aluminum oxide shop rolls, diamond files, polishing wheel, air compressor, proper tools, cleaning, lube, etc.

        For the Warthog soften the sharp edges surrounding the “mag well.” Soften the edges on the receiver/mag tube feed ramp. Soften the edge all around the trigger group shell ramp and polish the ramp surface. Other than a very good cleaning and lube nothing needs to done to the trigger group. Some Citadel models are easy to fully seat the barrel and some are not. The one I received required coordinating tightening the mag cap with the threaded ring that secures the forearm. The rail secured to the receiver with allen head set screws needs blue loctite applied to the set screws. Front sight set screw needs to be replaced with a longer screw. This should be more than enough for you to be already on your way to making an informed what to do and what to expect purchase. Let me know how it goes.

  10. avatar Matt in Oklahoma says:

    It looks interesting but it’s a terrible time to release a new weapon without ammo

  11. avatar busybeef says:

    Cool gun but for $900 nothing beats the Sig Sauer Legion in Carry Optics or Production at the moment.

    And I say this as someone competing with a CZ Custom that cost twice as much.

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