the IR sight puts your killmode up! its great for Metro in the ticket station, or tehran highway, or pretty much anywhere! its great!
I rock M249, IR scope, bipod and extended mag
although for my engy class
SCAR with IR fore grip and heavy barrel
for those on PC my tag is Robeenio
one thing I have noticed is that the game REALLY favours squad work, yeah you can do a bit of lone gunman action but you don't get anywhere near the amount of points that a few guys running round together do, covering each others backs, reviving scouting etc.