Yeah, its frustrating. I just had a sniper aim a meter away from me and kill me in 1 hit.
were you moving? snipers lead their shots on moving targets.
but i agree lag drives me crazy too. i hate when you unload a whole clip but killcam shows you facing the wrong way!
As a matter of fact I was moving. The thing is, he didn't lead in front of me, he shot far behind me.
Sometimes the killcam is affected by lag, too. I presume what it does is record the key input of players and their alive/dead state (not health, since red never appears). If not all that information is available in time, it is inconsistent with how things actually happened.
Also, just for kicks, I'm crossposting this:
http://www.cod4central.com/forums/general-discussion/killcam-tactics/