Amplified Fury

I honestly didn't know how to describe this in the topic title, but it seems in matchmaking lets say, hemorrhage team snipers, that when i'm looking at someone, and i can barely JUST barely see the tip of their head, they snipe me. It seems it would make sense that in order to even see me, i need to completely see their head. It was kind of like this in halo 3 also. It really bothers me that i basically don't get a shot against him while he blows me to bits.