@Kylie
In real life however, if someone was doing that, you wouldn't follow his head :P You'd just wait at his head level and trace him till he pops up again, then bam head-shot xD They made the ironsights more for pin-point aiming then general firing. It's for those hard to hit time's or if someone's in the distance. I think it works well ^^
From 0 to KICKASS in .stupid seconds.