FN 509 Apex Flat Trigger Review | All Hail The Flatty

FN 509 Apex Flatty Trigger
FN 509 Apex Flatty Trigger

U.S.A. – (Ammoland.com) – The FN 509 made a huge splash last spring with shooters that were looking for a pistol that has a full-size grip and a shorter, commander length slide. I was lucky enough to receive not one, but two examples for testing in early 2017. The best part about it? FN was kind enough to fit a pre-production FN 509 Apex flat trigger in one of the guns at the factory. Huge thanks to Tom and Kristina at FN as well as Paul at Apex for making that happen.

Why upgrade the trigger?

Now the first question that you might be asking is why should I upgrade the trigger on my FN 509, it is pretty solid out of the box and I don’t think that it needs anything. After shooting the flatty trigger side by side with the factory FN 509 trigger, I have to say, it is absolutely a worthwhile upgrade.

What’s in the box!?!?

Inside the box, you will get the flat trigger mated to Apex’s own trigger bar and a sear. I am told install will be straightforward and easy, sadly I do not have the first-hand experience with that since the trigger was installed by FN when the gun was assembled.

Trigger Weights

First, let’s look at the overall trigger pull weight. The factory 509 trigger weighs in at approximately 6 pounds 4 ounces on my Timney Triggers scale. I find that the manual trigger gauges are slightly more accurate than the electronic versions and tend to use the Timney gauge far more often than my Lyman electronic gauge in case you were wondering.

The stock trigger pull comes in at 6 pounds 4 ounces.

With the Apex flat trigger installed on the FN 509, the trigger pull weight drops to a very palatable 5 pounds on the nose as measured on the same Timney trigger pull gauge. There are a few other redeeming qualities about the Apex trigger that make it a clear choice if you are looking for a better shooting experience from your FN 509.

The upgraded Apex flat trigger results in a 5 pound trigger pull on the nose.

Overall Comparison and Feel of the Triggers

The overall trigger reach is just about perfect for average size hands and the trigger shoe does a great job of locating your finger in exactly the same place on the shoe thanks to a small kick out at the bottom of the shoe. Take up is minimal and you find a reasonably well-defined wall as soon as the striker is finished with its cocking stroke. Cocking stroke? You might be confused.

The Fn 509 is technically a double action pistol so the striker needs to be partially cocked when the trigger is pulled resulting in some nice resistance as you mash your finger onto the nicely finished face of the trigger.

Take up with the Apex trigger is minimal.

Once the trigger reaches that wall the break is reasonably crisp, but not single action trigger good as you would expect. Asking a pistol that is effectively a double action striker gun to feel like a match 1911 trigger is not even close to reasonable. The trigger overtravel is minimal thanks to the cleverly designed overtravel limiting finger on the back of the trigger.

Overtravel is minimized by a spur on the back of the trigger shoe.

Thankfully Apex included a trigger safety on the new part to retain the drop safe qualities of the pistol. The last thing anyone needs is a gun that goes bang when dropped. You can see here how minimal the travel of the trigger is when compared to the above photo.

Apex has fitted a blade style trigger safety to the flat trigger shoe.

So what about the factory trigger? It is combat quality, but not too bad. Take up is much longer because you not only need to cock the striker but also depress the trigger safety. This results in the trigger pull feeling longer than it actually is.

Perceived take up on the stock trigger is much longer.

The break on the factory trigger is nowhere near as well defined as it is with the Apex unit but is still very serviceable.

Overtravel is greater with the factory trigger but it isn’t too bad.

The trigger safety on the factory part is reminiscent of FN’s FNS pistols or similar to the M&P style of hinged trigger. I don’t have much preference for a hinged trigger or a dingus style trigger safety, it just doesn’t seem to impact my shooting in any appreciable way.

The factory FN 509 trigger uses a hinged trigger design like its older siblings.

Looking closer at the back of the factory trigger you see how FN incorporated the trigger safety and overtravel stop on the factory polymer trigger. It isn’t a bad design but is certainly designed with combat shooting in mind.

Overtravel on the FN trigger is controlled with some plastic shelves on the trigger shoe.

The Apex flatty achieves the same results in a much more elegant design. The overtravel stop is large and very functional. You also see that Apex used a blade type trigger safety that is more conducive to target shooting in my humble opinion.

Apex uses a much more pronounced spur on the back of the shoe to control overtravel.

Apex also uses the same high-quality aluminum for the trigger shoe that they do on their entire lineup, a step above the plastic trigger if I do say so myself. The face is smooth with no serrations much to my excitement. As contrary as it might seem, I prefer to allow my finger to slide slightly as I pull the trigger due to the size of my mitts.

The Apex trigger features a flat, smooth face.

FN’s factory option is slightly less forgiving when sliding my finger across the face slightly during the trigger depress but does feel decent if you are used to the shape of FN or SIG trigger shoes.

The FN trigger is rougher and curved.

Shooting Impressions

While these groups were shot before I spent some serious time working drills to remove the slight pre-ignition push habit that I have developed, they do tell a very clear story or three. One, I needed to spend some serious time working on fundamentals. Two, I need to drift the rear sights slightly to center my group. Three, the more crisp trigger that the Apex Flatty delivers does wonders when comparing the two triggers back to back.

10-yard group with the FN trigger.

The improvement on the 10-yard groups was nothing short of eye-opening. The reset on the Apex unit was tactile, short, and positive resulting in quick follow up shots.

The 10-yard group with the Apex trigger was a marked improvement.

In conclusion, I can wholeheartedly recommend the Fn 509 Apex flat trigger. The feel of the trigger is hands down better than it is in stock form and the price point should be reasonably palatable, unfortunately, we don’t know what the MSRP will be until it is offered on the general market since at the time this post is being written only pre-production units are available.

Check out Apex Tactical on the Apex website for more information.

Upgraded Apex flatty on the bottom, stock FN trigger on top.

About Patrick R.Patrick Roberts

Patrick is a firearms enthusiast that values the quest for not only the best possible gear setup, but also pragmatic ways to improve his shooting skills across a wide range of disciplines. He values truthful, honest information above all else and had committed to cutting through marketing fluff to deliver the truth. You can find the rest of his work on FirearmRack.com as well as on the YouTube channel Firearm Rack or Instagram at @thepatrickroberts.

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Daniel Webb

Do yall know if the trigger will work with the new 509 tatical that just came out if not will yall make one

Roy Boy

Blip zip


Apex needs to get the lead out. Thanks for the only 2018 news update so far

Andrew Brown

The FN 509 has been a big disappointment for me. From the mag release to the release of this trigger. Empty promises if you ask me.


Hey Patrick, is there any word on a public release for this trigger

Francis Marion

Please dear god let this thing be released soon. I’ve been dying to put one in my FNS-9 and FNS-9C since SHOT last year.