Approximatly 1,230 meters..... or 4,035 feet.....and its a headshot !!!
Full screen and HD to appreciate it.

http://www.youtube.com/watch?feature=player_embedded&v=bJThk6EdXaA

Not shot by me btw....

Nice.

This is one reason why I enjoy the battlefield franchise.. Real bullet drop and flight time..   it's not just pixel mapped like most fps games..  

That was a great shot.