• Reduce your trigger pull from 7.25lbs to a modified 4.25lbs (Average results can vary up to +/- 1lb)
  • Improve accuracy and overall FN 509 Performance
  • Solid 40% Trigger Pull Reduction!
  • Custom FN 509 Aftermarket Trigger Upgrade!
  • Also functions in 509C, 509C Tactical, and FNS Models!
  • Will NOT function in FNX Models.
  • Highest Quality American Spring Steel ASTM A228 Music Wire
  • FN 509 Trigger Kit includes a Custom Lighter Sear Spring, Disconnector Spring, Striker Spring and Striker Block Spring
  • Protected by the M*CARBO 100% Lifetime Guarantee
  • Made in the USA!
  • Fast Same Day Shipping!

FN 509 Trigger Spring Kit

  • Custom Lighter Sear Spring
  • Custom Lighter Disconnector Spring
  • Custom Lighter Striker Spring
  • Custom Lighter Striker Block Spring

Custom FN 509 Trigger Job to reduce trigger pull from a factory 7.25lbs to a modified 4.25lbs, giving you a 40% FN 509 Trigger Pull Reduction! Best FN 509 Trigger Upgrade for Increased Performance. Lighter and Smoother FN 509 Trigger Pull and Improved FN 509 Trigger Reset. Custom FN 509 Accessories by Combat Veterans! Best FN 509 Aftermarket Parts to get the Most Performance out of your FN 509 Pistol! 

The FN 509 Trigger Mod is a must have for FN 509 Aftermarket Trigger Upgrades! Improved Accuracy with Custom FN 509 Trigger Upgrade designed by Combat Veterans! Best way to improve the FN 509 Trigger with Custom FN 509 Trigger Spring Kit by M*CARBO! Corrects Problems with Factory FN 509 Trigger.

Custom FN 509 Trigger Upgrade to Improve Performance and Accuracy! If you have ideas for more FN 509 Accessories send us an email! help@mcarbo.com

Best FN 509 Upgrades for Competition Level Performance!

FN 509 Owners Manual & Exploded View:

If you're getting the FN 509 Trigger Spring Kit, then you might find the following FN 509 Resources useful in further enhancing your firearm. Download the FN 509 Owners Manual to plan your next firearm project.

M*CARBO No Hassle 100% Lifetime Guarantee:

The FN 509 Trigger Spring Kit is protected by the M*CARBO No Hassle 100% Lifetime Guarantee.

M*CARBO Lifetime Guarantee

Drop Tested and Approved:

FN 509 Trigger Spring Kit is built with M*CARBO ASTM Spec Springs that will offer a perfect trigger pull reduction with an unlimited drop test rating (3", 6", 9" & 12"+).

Tested and Approved:

The FN 509 Trigger Spring Kit has been tested repeatedly with numerous brands of ammunition to ensure reliable operation and safety.

Veteran Owned and Operated Business:

American made FN 509 Trigger Spring Kit designed and manufactured by Combat Veterans. We will donate a portion of your purchase to the Military Foundations we humbly support.


You must be 18 yrs of age to purchase. We advise that all parts purchased from our inventory be installed and inspected by a qualified gunsmith. Modifying your weapon may be prohibited in your state. Do not modify your sear or hammer engagement surfaces, with or without the FN 509 Trigger Spring Kit. Before installing please be sure to check all local state and federal laws. By installing this part you agree to take full responsibility for any and all legal, health and warranty consequences that may be incurred.

Overall Customer Rating of 112 Reviews:


The video that these guys put up to help is as good as it could possibly be. I have shaky hands and minimum gun smith skills but with some patience and listening closely to the tips the installer gives in the video, I was able to get this job done. I don't have a trigger pull weight but there is a major difference. I also took the time to follow another video on how to get some grit out of the trigger and did that at the same time. My trigger still has some annoying grit but the pull is amazing and crisp. It's crazy what a difference this kit made.

Houston TX

Great upgrade to the FN 509

Installed this on a 509 tac, reduced trigger weight, smoother shorter take up, shorter reset, great addition to the Apex trigger, turned this gun into a truly excellent shooter.


FN 509 Much Better

Followed the video on YouTube and it made the install pretty easy. I was nervous about doing it and figured worse case I'll take it to a gunsmith to finish it up.

I bought wrong spring kit...my fault. M*CARBO quickly shipped me the correct kit. Excellent customer service!!

Does what it says and more

It does lower the trigger pull weight to the firearm. However, at the expense of reliability. I hadn’t had an issue for the first 50 rounds. Since that time though I’ve had an issue with one round for every 15 I shoot.

Fn 509 spring kit

I bought the 509 spring kit to pair with my apex trigger in my 509t. Installation of the spring kit was fairly simple and with a quick video review if the sear housing anyone should be able to do the job. I have noticed a significant decrease in trigger pull weight compared to the stock 509 and some of the take up grit has gone as well. I’d definitely recommend this product to anyone who wants a lighter trigger pull and a better reset to their gun.

Number of questions: 0