First shot was definitely WTF??!! but I can see that he was obviously aiming where enemies would show up, esp on crackhouse, where its obvious as to where ppl are going to rush or camp; second was dead on and third shot are recoil HS. I say no hacks, some skills and some luck involved and voila, there you go, HeadShots.

Just my 2˘, if it matters. If you still think that player hacks plz provide more proof.