i never played BF3 online, but i salute those guys in BF4 who still lands head shot ( not sure if hacker) from where i cant even possibly spot em even in the death cam. Has an assault rifle, has 300 ms + ping.
I read the bullet velocity, muzzle suppression, target leading, effective projectile drop curve all these come into picture. Even after all this, if he shots me multiple times from like a light-year away with a petty rifle!! , then O.K. I am a noob, i dont know how to play BF4 and i wont land any headshot in near future like he did.. I am happy with it.