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Review: FN 509 9mm

Review: FN 509 9mm
The polymer-frame, striker-fired, 17-round FN 509 9mm pistol was designed to compete in the U.S. Army's Modular Handgun System trials, and it's now available to civilians.

The U.S. Army's search for a standard-duty pistol toreplace the Beretta M9 ended in January 2017. SIG SAUER won the militarycontract. Civilian shooters also won because the competition among the variouspistol manufacturers resulted in an all-new group of top-performinghigh-capacity, polymer-frame pistols.

FN America's entry in the military trials (known asthe Modular Handgun System program, a.k.a. MHS) is the FN 509, and it's theresult of years of rigorous research, development, and testing. The FN 509 maylook to the casual observer to be just another highly refined, polymer-frame,high-capacity, striker-fired 9mm pistol, but there's more to it than meets theeye.

Its Bones

Featuring a full-size, all-four-fingers-fit polymerframe, the FN 509 is serialized on the bottom of the dustcover via a steelplate mortised into the accessory rail rather than on a steel skeletoncontained inside a removable polymer frame shell. As such, the frame size ispermanent and can't be converted into a compact version.

Machined from stainless-steel bar stock,the slide is finished in matte black. It has a deeply flared ejection port, andthe external extractor acts as a visual and tactile loaded-chamberindicator.

As for the slide, it's machined from stainless-steelbar stock, features modern contours and sights, and houses a 4.0-inch barrelthat cams up into the massive ejection port to lock into battery. Barrel andslide are finished in matte black via a ferritic nitrocarburation processsimilar to nitride. As mentioned before, it's of striker-fire design, and themagazine capacity is 17 rounds.

However, these facts don't begin to do justice tothe FN 509. Design features are deeply researched and finessed toperformance-enhancing perfection. The stainless slide features tapered sidesfor easy holstering, a lowered and flared ejection port for reliable ejectionof empties and unfired cartridges, and drift-adjustable sights front and rear.Luminescent three-dot paint offers low-light performance. (Tritium night sightsare available for law enforcement.) Made of steel, both sights are robustenough to pound spikes. The rear sight offers a vertical front face useful forracking the slide one-handed on a belt, steering wheel, concrete curb, orwhatnot.

The forward end of the external extractor isengineered to protrude slightly when a round is chambered. It provides a visualand tactile loaded-chamber indicator.


FN is renowned for its cold-hammer-forged barrels,and the FN 509's tube is manufactured in-house. Made of stainless steel, itfeatures a polished feedramp and chamber and a recessed target-type crown. Notonly should FN 509 barrels prove to be accurate, but also they should offersuperb barrel life, corrosion resistance, and durability.

Uniquely, the FN 509 is fully ambidextrous, so youdon't need to remove and swap controls from one side to the other. There's amagazine release button and a slide lock lever on each side. The grip is wellcontoured for a high, recoil-controlling grasp and features three distincttextures: a "dragon scale" raised-square pattern on the frontstrapand backstrap, coarse checkering on the side panels, and a stippled-typepattern on each side of the upper panel just above and aft of the magrelease.

Each FN 509 pistol ships with two differentbackstraps. The factory-installed backstrap is curved; the spare is a slenderstraight-backed version. This enables the user to tweak grip diameter and feelto suit his or her hand. Tools are required for the swap. Drive out the tinyretaining pin, exchange the backstraps, and replace the pin.

Three different textures grace the FN 509'sgrip, and a lanyard loop is located at the bottom of the interchangeablebackstraps.

A low "fence" protects the slide lock fromaccidental activation, and the trigger guard is engineered large enough forcomfortable use with gloves. My two favorite frame features are at the bottomof the grip. First, there's a lanyard loop. Originally added to military revolversin cavalry days to prevent the loss of an empty sidearm if a mounted trooperhad to drop it and draw his saber, it's a feature that has somehow hung on andis still included in many military sidearm specifications. Each MHS contenderI've examined included a lanyard loop. As a horseman from way back, I find thelanyard loop lends a little nostalgic charm to an otherwise thoroughly modernpistol.

Second, the grips are scalloped on each side justwhere they meet the magazine's floorplate, allowing for a good grip in case themagazine needs to be manually torn out of the gun to clear a stubbornmalfunction. On a related note, the forward edge of the magazine's floorplatehas a sturdy lip extending just enough that it could be hooked on something andthe magazine pried out one-handed should the need arise.


As for the magazine, it's steel with a fully weldedseam. Perforations enable the shooter to instantly see how much ammunitionremains. The high-visibility orange follower is constructed of a low-frictionmaterial. Two 17-round magazines are included with each pistol, and 10-roundversions are available for states with capacity restrictions.

Field stripping the FN 509 is quick andeasy. Note the permanently imbedded steel skeleton inside the polymershell.

The FN 509's trigger features the hingedtrigger-shoe safety popular today, and it has a nicely rounded contour thatfeels good under the trigger finger. Basically of two-stage design, there'ssignificant take-up, then a crisp wall against which the shooter may stage andsqueeze through when a precise shot is required.

In addition to the hinged trigger-shoe safety, theFN 509 features an internal safety that blocks the firing pin unless thetrigger is squeezed rearward. No version with an external manual safety isoffered, at least not initially.

Field stripping is fast and easy. Drop the magazine,clear the chamber, lock the slide rearward, and rotate the takedown lever onthe left side of the pistol 45 degrees until it points downward. Release theslide, squeeze the trigger, and draw the slide assembly forward off the frame.Lift the captured recoil spring assembly and barrel out of the slide and you'redone.

To reassemble, replace the barrel and recoil spring,align the slide on its rails, slide it rearward and engage the slide lock.Rotate the takedown lever to its horizontal position.

1. Hornady Critical Defense 115-Gr.FTX
2. American Eagle Syntech 115-Gr. TSJ
3. SIG SAUER 115-Gr. JHP
4. Black Hills 125-Gr. HoneyBadger
5. Speer 147-Gr. Gold Dot
6. Federal 147-Gr. HST
7. Browning 147-Gr. BXP

Range Results

During the 2017 SHOT Show I attended a prelaunchintroductory event for the FN 509 and put several hundred rounds through one.Distance was limited and light was poor in the indoor range, but my initialimpression was that the FN 509 possessed unusually good ergonomics, and thatimpression strengthened the more I shot it.

Several months later, after receiving another FN509, I ran a collection of my favorite 9mm ammo through it at my home shootingrange. In all, I put close to 200 rounds through it during an extensiveshooting session. I found the pistol to be 100 percent reliable. It balanceswell and points naturally.

As part of the MHS requirements, competing modelswere required to meet some impressive accuracy and reliability criteria.Pistols were expected to offer a 35,000-round service life, which, for obviousreasons, I couldn't test. On the other hand, each competing model waschallenged to keep nine of 10 shots inside a 4-inch circle at 50yards- that I could test.

The FN 509 achieved good accuracy withseven different 9mm factory loads. Four produced five-shot average accuracyunder 3 inches at 25 yards; all were under 4.5 inches.

After completing my standard 25-yard accuracy testsby firing three consecutive five-shot groups for average with each type ofammunition, I chose the most consistent- whichwas the Federal 147-grain HST- moved my target tothe 50-yard line, and fired a 10-shot group. I managed to keep six of the 10 ina 4-inch group. At that point, it became clear that my middle-age eyesight wasproviding a bit of a roadblock and no doubt the FN 509 would have performedbetter from a Ransom Rest.

As the accompanying chart indicates, the FN 509averaged less than 3 inches at 25 yards with four of the seven factory loads Itested. That's not bad- certainly within acceptable fighting-pistol parameters-but it's not match-winning accuracy, either. Candidly, I struggled with thetrigger.

As I mentioned earlier, the trigger is essentially atwo-stage type. And on my pistol, the trigger's first stage gave me fits.Rather than a light, smooth swing through to the second stage, it is heavy and-for lack of a better word- rubbery. The trigger's reset isn't as short as some,but it is nice and distinct. Factory specs rate FN 509 triggers at between 5.5and 7.5 pounds from the factory; measured on my Lyman digital trigger gauge, mypistol averaged 6 pounds, 11 ounces over a series of five measurements, with 7ounces of variation.

The trigger's rubbery feel made it difficult for meto achieve a perfectly clean release while shooting for accuracy. It's a shame.Judging by the occasional outstanding group I did produce, I think the FN 509has inherent accuracy, but it's just difficult to tap into without a reallycrisp trigger. Perhaps several hundred rounds worth of break-in would clean upthe trigger's feel, and maybe, just maybe, evetually some company will offer areplacement trigger for the FN 509.


With my formal testing complete, I put up a couplesteel torso plates and ran a series of informal drills to more thoroughlyevaluate the FN 509's handling characteristics. Failure drills, Bill Drills,and casual shooting at "threatening" dirt clods revealed the pistol'svirtues. It points naturally, balances well, and recoils politely. Reliabilitythroughout my entire shooting session was stellar, just as you'd anticipate ina pistol built by the company that supplies the bulk of our armed forces'machineguns.

I haven't fired all the pistols submitted for theMHS program, but I've shot many of them, and each has been outstanding. Whilethe FN 509 did not win the coveted military contract, it is a fine servicepistol, and it stands among an elite group of the best-designed polymer-frame,high-capacity pistols available. Like a trusty workhorse, it will providedependable service at the range, on duty, and in defense of the home.


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