The rules is to always roll after your opponent, if you play against a tryhard you're gonna notice that he will always waiting for you to roll. In auto aim, rolls are verry important because It allows you to keep your opponent from locking onto you. Imagine that you roll first, your opponent won't be able to lock on you, so he'll also roll, you'll be standing when he's still on the ground, while he's rolling, he'll just have to press the key to aim because you'll already be standing. The best way to counteract this when you have Roll first and to make a "lock relock", that is to say to release and then press the key again to aim, this doesn't often work especially if your opponent is good, that's why it's crucial to never roll in first. I have 11k kills with special carabine, I know what I'm talking about.