Action Enhancement Kit for FN 509 – with Curved Trigger

This Action Enhancement Kit for the FN 509 (with Curved Trigger) is a direct drop-in replacement trigger system that addresses the factory trigger’s primary shortcomings: excessive pre-travel, long reset, and a mushy break. By replacing the trigger body, sear, and associated springs, this kit delivers a consistent pull weight of approximately 5.5 lbs. with a defined, crisp break and a significantly shortened reset. The patent-pending design incorporates a center-mounted pivoting safety that retains factory drop-safety values, making it suitable for duty, competition, and personal defense use.

Compatibility

• FN 509 (all standard models)
• FN 509 Compact
• FN 509 Tactical
• FN 509 Midsize
• FN 509 LS Edge (verify fitment with slide profile)

Key Features

• Pull Weight: ~5.5 lbs. (verified with gauge; factory trigger typically 6.5–7.5 lbs.)
• Reset Distance: Reduced to ~0.10″ (factory ~0.25″) – measurable improvement for split times
• Break: Crisp, no creep after wall engagement
• Pre-Travel: Reduced by ~40% vs. factory
• Over-Travel: Minimized via integrated stop
• Safety: Center-mounted pivoting safety maintains factory drop-test compliance (verified per SAAMI specs)
• Installation: Drop-in; no fitting, filing, or polishing required. Uses factory trigger pin and frame components

Install Difficulty

2 out of 5 – Basic. Requires: 1/16″ punch, small hammer or brass punch, tweezers for spring handling. Detailed instructions included. Average install time: 20–30 minutes. No trigger gauge or armorer-level tools needed.

FAQ

Will this trigger work with my FN 509 if I have a manual safety?

Yes. The kit is designed to interface with the factory manual safety lever. No modifications to the safety mechanism are required.

Why does the sear color differ from the product photo?

The sear you receive may appear different from the photo due to variations in the anodize or nitride process. If the Apex logo is laser-engraved on the sear, it has passed all necessary processing and is functionally correct. Color does not affect performance or durability.

What if I order the Flat Dark Earth (FDE) trigger and dislike the color?

Due to the anodize process, FDE triggers may appear as a burnt bronze color. This is a repeatable finish, but if you are unsatisfied, contact our Customer Service team to discuss exchanging it for Red or Black. We apologize for any inconvenience.

Shipping & Warranty: Ships within 1 business day via USPS Priority or UPS Ground. This component carries a limited lifetime warranty against manufacturing defects. See full warranty terms at checkout.