I have a buddy with a couple FNS pistols he put Apex triggers in and he says the difference is night and day for how the trigger pull feels after the kit install. I keep looking at those new 5' FN509s but I hate to put the money into another pistol that won't meet my group size expectations.

The FNS has so many features I like I'd carry the damn thing if I could get it to shoot groups like my P07 does. It's not so bad if you practice enough with it to get used to it. I have no idea if that's required to move that big as striker fast/hard enough to ignite the primer or if they did it to make the trigger pull heavier so as to make the gun more appealing to LE Departments since those pistols will never have a light, or 'hair' trigger. So the FN design uses the trigger to put increased compression on the striker spring to move the striker fast/hard enough to set off the primer of the round in the chamber. When you pull the trigger for the next shot the sear (the whole thing) moves to the rear to further cock the striker, before it starts to rotate downwards at the rear to release the striker. But (the big but) is the sear is forward of were it was when it released the striker to fire the pistol. With the FN design the slide goes forward and the sear catches the striker. after the Apex install and has worn into a nearly 2&3/4 lb. When you pull the trigger the sear rotates downwards at the back to release the striker. The M&P slide goes forward, the sear catches the striker and holds it. It's the design of the trigger/sear function. You're not going to get an Apex triggered FNS or FN509 to compare to and Apex triggered M&P.

Youtube apex tactical trigger install