Action Enhancement Kit for FN 509

This drop-in Action Enhancement Kit for the FN 509 directly addresses the factory trigger’s excessive take-up, spongy break, and long reset. By replacing the OEM trigger and sear components, this kit reduces pull weight to approximately 5.5 lbs., shortens pre-travel and over-travel, and delivers a clean, crisp break with a tactile reset. The patent-pending design maintains factory safety values via a center-mounted pivoting safety, and requires no fitting—direct drop-in for standard 509 frames.

Compatibility

• FN 509 (all generations)
• FN 509 Compact
• FN 509 Tactical
• FN 509 Midsize
• FN 509 LS Edge (holster clearance may vary)
• Not compatible with FN 509 CC Edge or FN 545

Key Features

• Pull Weight: Approx. 5.5 lbs. (measured with digital gauge, standard spring set)
• Reset Distance: Reduced ~40% vs. factory; audible and tactile
• Pre-Travel / Over-Travel: Minimal—adjustable via included set screws (locktite recommended)
• Trigger Break: Clean, no creep after break-in (~200 cycles)
• Safety: Factory drop-safe; center-mounted pivoting safety bar maintains sear engagement
• Installation: No filing, polishing, or fitting. Direct drop-in using factory pins and springs
• Trigger Styles Available:
  – Classic: Radiused front corners, flat sides, no face cuts
  – Type 3: Chamfered front corners, decorative face cuts on sides (identical internal geometry and pull weight)
• Finish: Black anodized 6061 aluminum (FDE discontinued per current supply chain)

Install Difficulty

2 out of 5
Tools needed: 1/16” punch, small hammer, #0 Phillips screwdriver, blue Loctite. Remove slide and barrel, drift out trigger pin and sear pin, swap components, reassemble in reverse order. Trigger over-travel set screw adjustment requires fine-tune. Approximate time: 20–30 minutes for first install.

Frequently Asked Questions

Will this work with the FN 509 Compact?

Yes. The kit uses the same trigger and sear housing geometry across all 509 full-size and compact variants. No additional parts needed.

Does this kit reduce pull weight below 5.5 lbs. with lighter springs?

The kit ships with standard springs calibrated for 5.5 lbs. minimum. Using aftermarket lighter striker springs may reduce weight further but may compromise ignition reliability. The manufacturer recommends staying with included springs for duty or competition use.

I received a trigger with a different color than expected. What are my options?

FDE triggers have been discontinued due to anodizing supply issues. If you received an FDE trigger and are unsatisfied with the color, contact customer service to discuss replacement with red or black. Stock availability varies.

Shipping & Warranty

Ships within 1–2 business days via USPS Priority or UPS Ground. Lifetime warranty against manufacturing defects. Overtravel set screw adjustment is user-serviceable; improper adjustment that causes safety issues voids warranty. Contact support for return authorization before sending any components.