Action Enhancement Kit for FN 509

If you own an FN 509, you already know it’s a solid pistol right out of the box. But the trigger? That’s where a lot of us feel there’s room for improvement. This drop-in kit was originally developed specifically for the 509, and it’s been a go-to for owners who want a cleaner, lighter pull without sending the gun to a smith. It reduces pull weight to around 5.5 lbs, shortens pre-travel and over-travel, and gives you a crisp break that makes it easier to shoot accurately. The best part? It drops right in—no filing, no fitting, no headaches.

Will this fit my FN 509?

This kit is designed for the FN 509 series. Check your model:

• FN 509 (full-size)
• FN 509 Compact
• FN 509 Tactical
• FN 509 Midsize
• FN 509 LS Edge
• FN 509 CC Edge

What you get with this kit

• Drop-in install – No gunsmithing required. Remove your stock trigger assembly, drop this one in, and you’re done. We’ve got install videos linked to walk you through it.
• Reduced pull weight – Approximately 5.5 lbs, down from the factory’s heavier pull. Noticeable difference on the range.
• Short reset – The reset distance is tightened up, which helps you stay on target for follow-up shots.
• Center-mounted pivoting safety – This maintains the factory safety values, so you’re not giving up peace of mind for performance.
• Two trigger styles – Choose the Classic (rounded front corners, flat sides, no face cuts) or the Type 3 (chamfered corners with decorative face cuts). Both perform the same, just different looks.

Install difficulty: 2 out of 5

This is a straightforward swap. You’ll need a punch set, a small hammer or mallet, and maybe a vise block if you want to be extra careful. Plan on about 20-30 minutes if you’ve done a trigger before, maybe 45 if it’s your first time. We recommend watching our install video before you start—it’ll save you a headache.

Frequently asked questions

Does this kit work with the FN 509’s factory striker and sear?

Yes. This kit replaces the trigger and trigger bar assembly only. It works with your existing striker, sear, and springs. No other parts needed.

Will this affect the gun’s reliability with self-defense ammo?

This kit is designed to maintain factory safety values. The trigger pull is lighter but still within a safe range for defensive use. That said, always test your carry ammo at the range after any trigger work—standard practice for any firearm modification.

I see two trigger styles. Which one should I pick?

Both perform identically. The Classic has a simpler look with rounded front corners and no face cuts. The Type 3 has chamfered front corners and decorative cuts on the sides. It’s purely cosmetic—pick the one that looks best to you. (Note: FDE color is currently unavailable due to supply issues. If you got an FDE trigger and aren’t happy with the color, contact our customer service to swap for red or black.)

Shipping & warranty: We ship from our family-run shop within 1-2 business days. This kit comes with our standard warranty against defects in materials or workmanship. If something’s off, reach out—we’ll make it right.