FNP series is discontinued. The FNX was it's replacement. There were a few refinements/changes made.
1. FNX has ambi safety-FNP has a reversibly one. You could get the FNP in decock only (no safety) if you like. FNX has aggressive grip texturing, lower bore axis, polymer lower profile safety/decocking lever's, slightly lighter, slightly different rail, deep v rear sights and big dot front sight and a flat-top slide. Mags are also 17 rounds in the FNX and it has more back straps and uses a plastic tab to retain them instead of the screw on the FNP back straps.
2. FNX is a scaled down version of the FNP 45).
3. The FNP could be completely stripped (fire control group can be taken out without drilling through the decocker lever). Some prefer the smoother grip, and it can be had in just decock only.
This post was edited on 5/6 at 12:34 pm