FN FNX-9 Recoil Spring / Guide Assembly, Black

I purchased this spring assembly as part of an effort to convert my FNX-40 to 9mm using an EFK Dragon conversion barrel. The original 40 S&W spring wouldn't cycle normal 115 grain ammunition reliably, so I purchased this spring assembly in hopes it would handle the ammunition better. The results were initially disappointing. This spring was very stiff out of the package and had worse performance than the original with failures to cycle every single round. I couldn't tell a difference between this and the 40S&W spring when manipulating the slide. I decided to store it in a fully-compressed state for a few weeks and began firing 124 grain ammo, which then allowed the firearm to cycle reliably. The failures are likely a combination of the barrel not being fully broken-in, the new magazines pressing too hard against the slide, and the stiffness of the new spring. I plan to keep the spring and continue shooting it, but If I were to try again, I might try to find a softer spring/guide assembly for my converted system.

Bought this since my FN-P9 needed a new recoil assembly. This fits and works. Quite stiff when new.