Action Enhancement Kit for FN 509 – with Curved Trigger

For FN 509 owners who want a better trigger without paying a gunsmith or chasing compatibility headaches, the Action Enhancement Kit with Curved Trigger is a direct drop-in upgrade. Apex originated the drop-in trigger kit for this platform, and the patent-pending design delivers measurable improvements to trigger pull weight and feel. At $160, this kit is a straightforward buy for anyone looking to get more consistent performance out of their 509 — no filing, no fitting, no extra parts needed.

Once installed, the kit cuts trigger pull weight to approximately 5.5 lbs. That’s a noticeable step down from the factory pull, making it easier to stay on target through the break. It also reduces pre-travel, over-travel, and reset distance. What that means on the range: a shorter, cleaner pull with less wasted movement between shots. The break is crisp, not mushy, so you feel exactly when the sear releases. Reset is positive and short — you’ll feel it click back into place without having to fully release the trigger.

Key specs and fitment notes:

• Direct drop-in replacement — no hand-fitting, no additional machining required
• Maintains factory safety values with a center-mounted pivoting safety
• Compatible with all FN 509 models (standard, compact, midsize, and tactical variants)
• Curved trigger shoe profile for a familiar, comfortable finger placement
• Pull weight: approx. 5.5 lbs (verified with standard trigger pull gauges)
• Reduces pre-travel, over-travel, and reset distance compared to factory trigger assembly
• Includes sear and trigger shoe — everything needed for the upgrade in one package

Important color and manufacturing notes:
Flat Dark Earth (FDE) triggers may come out closer to a burnt bronze color due to the anodizing process and materials used. This is a repeatable color — not a defect — but if you receive an FDE trigger and aren’t happy with the shade, contact customer service for a swap to Red or Black. The sear you receive may also look slightly different from the product photo. If the Apex logo is laser engraved on it, the sear has gone through all necessary processes and is correct.

What you actually get for $160:
A trigger that breaks cleaner and resets shorter than stock. No guesswork on compatibility. No extra springs or pins to order. No need to send the gun off to a shop. It’s a straight swap — remove the factory trigger assembly, drop this one in, and you’re done. For