Player is hacking, there is no doubt about it.

https://bf4db.com/player/battlereport/890260278215079744/1874136399

Damage modifier.  In this most recent example: http://battlelog.battlefield.com/bf4/battlereport/show/1/890492328109168640/1874136399/

He had 110 kills, 7 HS ribbons, 106 of 110 kills was with the Famas.  BR shows 38% kills/hit.  The very most he could possibly have is 33%, and that's if every one of the 4 kills of unknown weapon were done with 1 shot kills from 100% damage weapons.

The one from the battlereport BnH provides above is similar.   110 kills, 6 HS ribbons, 70 kills with AK-12 and 64% kills/hit reported.  Nope. 

Edit: 247FP Christmas Tree color display: http://prntscr.com/g1ezhg