Here is my tip, that always works for me since i end up in first place most of the time. Yes, i got an ego but i know when i am beaten by another ppl, so dont flame me guys. I have screen shots with ratios of 9kills 1 deaths, 14 kills 0 deaths and such. Anyway, SMGs r my main weapons, use them all the time. I dont try to aim from big distances, i am more of a close combat type of guy. I get close and aim for their head, i dont do small bursts or anything like that. The way i kill them is when they cant shoot at me (while they r reloading). What i mainly do is the usual, shoot at him and he shoots at me BUT, when i see that he is going to run out of bullets soon(takes about 3-4 seconds to use a full clip), I AM THE FIRST to do the reloading. U will be taking some fire from him coz u r reloading and he still have some bullets, but if u r good enough and u know that u will survive(enough health to take 1 or 2 more bullets) then u should reload before he does. That way, when it is his turn to reload, u will already be ready with 32 more bullets for him. Thats what i do and i survive all the time. I hope this helped, by the way, i usually aim for the torso, but if i am going up/down the stairs, it is easier to aim for the head, also if they r crouching (easier to hit their head as well).
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*GEL*DeathStrike[gm]
Gods Elite Legion
www.godselitelegion.s5.com