Accuracy Options

[gsx1000r02]

Ok so I am still new here on cod4. I am having trouble with accuracy on any weapon. But watching some of the other guys playin and wonder if there is any mods that they are using. It seems that they lock on too easy, I dont see how it is that I can drop a whole mag into someone, not kill them and they turn and lock on to me and drop one or two shots and I'm dead. I dont know if there is any adjustments that I can make to tweak my controller. I know the rapid fire mod. I have tried to make the changes that cod4 allows in their settings but nothing seems to work. Is there any tweaks that I can do, how can I improve my accuracy? It gets real frustrating sometimes.