My bet is on spending what you have on the graphics (and the 380/280x is fine, if you are not too worried about the future). If you do that first, then even a small overclock on the 860K should be sufficient for BF1, but just a guess:
http://www.gottabemobile.com/2016/05/10/battlefield-1-beta-5-things-to-know-right-now/
Other thoughts: Make sure your power supply has the head-room for a 380/280x (500+ watts). If not, the Nvidia 960/950 could be about 75 watts less for similar performance during game play.
Do you have Mantle turned on for BF4?:
https://www.youtube.com/watch?v=pAgiDJ2UgNM