WHAT'S IN THE KIT:
- 1 - Custom Lighter Sear Spring
- 1 - Custom Lighter Disconnector Spring
- 1 - Custom Lighter Striker Spring
- 1 - Custom Lighter Striker Block Spring
FN 509 Trigger Spring Kit
Designed by combat veterans, this custom trigger job will reduce your trigger pull from a factory ~7.25lbs to a modified ~4.25lbs, offering a substantial 40% reduction. Experience a lighter, smoother trigger pull and improved reset, making this upgrade a must-have for anyone seeking optimal performance from their FN 509.
Our FN 509 Trigger Spring Kit corrects issues with the factory trigger and is an essential upgrade for enhancing accuracy and performance. Ideal for those seeking competition-level performance, this kit is a significant improvement over the factory setup.
Upgrade your firearm with the best aftermarket parts and experience competition-level performance with our FN 509 Trigger Spring Kit!
FN 509 Resources:
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.
Drop Tested and Approved:
FN 509 Trigger Spring Kit is drop Tested according to SAAMI Standard Z299.5 rating (12" & 48").
Tested and Approved:
The FN 509 Trigger Spring Kit has been tested repeatedly to ensure reliable operation and safety.
ATTENTION:
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.
Trigger kit and titanium striker well worth it
Love my 509 but wasn't super happy with the trigger. So I ordered both the spring kit and the upgraded striker. Can already feel the difference. Love the installation videos, you guys are my go to for spring upgrades.
Sch00t3rMcGavin
Oooos I meant to give it a 5 star review lok
Happy with new springs
I love my .22 from fn so much that I needed a 9mm from them. So I ordered my new fn 509 cc edge xl . I was not disappointed at all untill I pulled the trigger back, I was starting to think I just wasted my money! Thank god for this trigger spring kit, I replaced every spring except for the sticker pin and now I’m shooting better very happy with this cheap upgrade. The installation video is easy to follow and only took me a half hour to change out the springs
Next level FN
FN is one of those companies that is always on the edge of destroying its competition and obliterating Glock ha! BUT! they always seem to just slightly miss the mark. The FN 509 has a super heavy trigger, but that's on purpose because certain law enforcement agencies tend to not train very well, and cops end up shooting them selves. IE Glock New York trigger. The stock FN trigger is not bad at all just heavy and takes practice. The M Carbo spring trigger kit takes your FN509 to the next level! The Instillation video they provide makes it super easy to install. Thank you M. Carbo
VirginiaRader
Commonwealth of Virginia
Excellent!
I previously bought all the apex upgrades for my 509, and was not impressed with the trigger. The pull was still over 5lbs... I bought the mcarbo spring kit and my trigger pull is now 3.5 to 4lbs.. much better! Highly recommended!
Amazing trigger weight pull reduction
Got the one for my FN 509T. Man it shoots like a charm. Shipping was so fast it was amazing. Love that they had videos for the installation
Another successful Install
This is the third FN I've put a spring kit into. Definitely worth the cost and the time to install. This time started with 5¾ lb pull. It is reduced to 4¼ lbs. and really smooth. You won't be sorry .
Excellent Trigger Upgrade
Excellent trigger upgrade for the 509 without having to spend money on a whole new trigger like an Apex. Install is easy , as you can put most of it together with one half of the trigger housing laying on its side rather than having to hold it all together while assembling, then place the other half of the housing and the disconnector in last. It lightens the pull noticeably while still remaining a practical duty/carry weight. It's by no means a crazy light and smooth match trigger, but definitely makes precise shots easier.
Any Chance you have something coming for the 510?
I already have an Apex trigger kit and an Apex striker installed. Could I use this kit just for the sear spring and the disconnector spring? Any harm in that approach? I'm guessing my Apex striker is too heavy for the firing pin spring and striker block spring. Thanks!
We think that it should work fine but we have not tested it with those components. We test all of our upgrades on OEM stock Firearms.
Will this spring kit work in the FN 545 model?
FN 509 Trigger Spring Kit is specifically designed for the FN 509 series and is not officially compatible with the FN 545 model. While the FN 509 and FN 545 share some design similarities, their internal components, including the trigger mechanisms, differ enough that the spring kit is not guaranteed to function correctly in the FN 545.
Answered by
FOXX /
May 6, 2025 11:43 AM
Hello, does it works with the FN 545?
Thanks
FN 509 Trigger Spring Kit is specifically designed for the FN 509 series and is not officially compatible with the FN 545 model. While the FN 509 and FN 545 share some design similarities, their internal components, including the trigger mechanisms, differ enough that the spring kit is not guaranteed to function correctly in the FN 545.
Answered by
FOXX /
May 6, 2025 11:44 AM
I’m also asking about the fn510 will the 509 kit work? If not please make a kit for a 510. Thank you.
NO, Some internal parts like the striker return spring are shared across the FN 509, 510, and 545 — but that does not guarantee full kit compatibility (especially with trigger and sear springs).
Answered by
FOXX /
May 6, 2025 11:45 AM
I’m also asking about the fn510 will the 509 kit work? If not please make a kit for a 510. Thank you.
I’m also asking about the fn510 will the 509 kit work? If not please make a kit for a 510. Thank you.
I’m also asking about the fn510 will the 509 kit work? If not please make a kit for a 510. Thank you.
I’m also asking about the fn510 will the 509 kit work? If not please make a kit for a 510. Thank you.
Will you be getting a spring kit for the new 510?
If this lighter spring kit is used with the Apex striker, which is heavier than the Mcarbo titanium one, would it presumably lessen the chance of light strikes?
Not compatible, apex striker is to damn heavy! But m carbo titanium striker is well titanium super light and strong so you will have better results.
Answered by
Patrick M /
November 28, 2023 4:42 PM
do your spring kits work with apex triggers like for the M&P or the FN 509 please let me know thanks also i was wondering if you fully polish the spring kits and other parts whether it be for a j-frame or M&P whatever the cause can you lower the trigger pull to get to that low end of the plus or minus 1 pound or possibly lower im looking for the lowest i can get on my double action only j-frame and other models please let me know thanks please get back as soon as you can thanks
In previous installations you’ve sanded and polished the striker block (example M&P Shield), will doing so with the 509 striker block be helpful and can be done or very bad idea?
It can recomended all depends if it is need it and how much polishing you will do.
I see it works with 509C, doesn't "specifically state" 509M - just want to make sure before I order along with the striker.
Yes, these parts will work in the 509M!
Will this fit the 509 Edge Long Slide?
GerryM January 6, 2023 6:03 AM
It also functions in 509C, 509C Tactical, and FNS Models, but I don't think we have tested it on that exact model; if the internal is the same and only the barrel and slide are longer, it can work.
Is this trigger spring kit compatible with the apex tactical trigger kit?
We only test with OEM parts; We can't say if it will work with APex
We only test with OEM parts; We can't say if it will work with APex
We only test with OEM parts; We can't say if it will work with APex
We only test with OEM parts; We can't say if it will work with APex
is this the same striker spring that comes with the striker kit?
November 29, 2022 8:54 AM
Yes it is! We include it at no extra cost with the striker to ensure safe and proper function of the lighter-weight Titanium Striker. If you choose to purchase both the spring kit and striker, then you will end up with a free spare striker spring.
Does the FN 509 Trigger Spring Kit work on the FN 509 Compact?
functions in 509C, 509C Tactical, and FNS Models
Is your spring kit compatible with the Apex trigger system? If so, what would be the expected difference combined?
We do not guarantee our spring kit with any other aftermarket parts, including the Apex Trigger System. We are, however, working on new upgrades for this model ourselves, which gives us better control to confirm compatibility! Please send an email to help@mcarbo.com if you would like to be notified directly for any new MCARBO upgrades for the FN 509!
Any options for the new 502 Rimfire version or any chance some of the 509 kit would help the 502 SAO 5 lb trigger?
We haven't tested any of these springs in the 502, but if you send us an email to help@mcarbo.com we will save your contact information along with your product request to our idea log!
It says it will fit FNS also so would it fit a FNS 40? If it does I would rather order order the same time for my 509T
I am sorry for our delayed response in the Q&A section. Yes this spring kit will work for your FNS 40!!
I am going to install the trigger spring kit in my FN 509 LS Edge. Besides the striker and striker block, what else would you suggest I polish? Really looking forward to the installation. The factory trigger is really "gritty". It was disappointing for a fairly expensive pistol. Thanks for the help.
Bob Turner
RWT January 10, 2022 3:17 PM
Each gun is a little different, I would look for any parts that show witness marks (wear) such as the trigger bar, if it shows signs of rubbing on the frame or another part, you can polish up that area to improve the feel. Use caution, to much polishing can be a bad thing. So take your time and do little by little.
Does this trigger spring kit function with my FN Five-Seven? If not, do you offer one for it?
We have not tested it for the 5 7 model so i would not advise trying it. Currently we do not offer one for the 5 7
Any reason this would not work with an Apex Tactical FN509 trigger? Thanks!
November 19, 2021 4:17 AM
I have been using this and have been pleased w/ the performance. I recently upgraded to the Apex Tactical performance trigger which includes a new sear. It feels that the strike seems weaker. Should I put back all of the OEM springs back or perhaps just the sear spring?
Thank you for contacting us, I believe the issue is with the APEX striker combined with our striker spring. If you would like to maintain the APEX striker I would swap back to the Factory striker spring, or you can swap back to the factory striker and maintain our spring. The difference in weight between the two strikers combined with the lighter striker spring can lead to light strikes, especially with reloaded or steel cased/surplus ammo.
Answered by
/
December 16, 2021 11:58 AM
If I bought this kit for the 509/c/t and only installed, let’s say just the striker firing pin spring and striker block spring to start? Would I see any potential benefits? Less grit? Less drag?
Hey Brother,
You will definitely see a reduction although we cannot give you a definitive amount. In regards to the smoothness and drag. So long as you polish some of the parts, you'll be good to go!
Will this function in the FN 509 LS Edge?
Hello, our FN 509 kit is compatible with all FN 509 models, including the LS Edge.