Every time I've seen the issue, (SA fine, no DA), it has ended up needing to go back to FN. What FNX model-9, 40,or 45? You may want to check for a cracked fire control housing. If that's the case you can either send it back to FN, or try to fix it yourself.
Parts listed here are designed for both the FN FNX-9 and FNX-40 pistol models chambered in 9mm/.40 S&W unless noted otherwise. MGW offers replacement magazines, barrels, slide assemblies, sights, triggers, springs, pins and more for these handgun models. Outfit your FNX-9/40 with quality OEM and...
Parts listed here are designed for FN FNX-45 pistol models chambered in .45 ACP unless noted otherwise. MGW offers replacement magazines, slides, firing pins, sights, barrels, springs, pins and more for this handgun model. Outfit your FNX-45 with quality OEM and aftermarket parts and components...