familiar
I'm pretty familiar with the P229/.40....SIG armorer cert x 3 and had about a 10 under my care when I was working.
-first thing I'd do is remove the extractor, pin and spring and clean the snot out the extractor recess and all 3 parts. There is a knack to removing and reinstalling the extractor and related parts, and it is easy to launch/loose one or all 3 installing or removing same, proceed with caution and understanding
-the advice on the recoil spring is sound, there is a correct way the spring fits on the guide rod......."tight is right". One end of the recoil spring is of a very slight lesser diameter than the other......AND THE TIGHT END GOES OVER THE GUIDE ROD FIRST. One would not think it matters, but it does. Incorrectly installed, it could rob from return velocity of the slide, thus the drag on the extractor
-There is of course the possibility of tired or worn parts. I(recoil spring, extractor, pin, and spring). But many feed issues are resolved with an armorers strip and clean. Be sure and clean your mags as well.