The most important thing is to not hold the trigger down so you the reticle has enough time to go back down after each shot. Make sure to aim down the sights since hip firing doesn't do any damage (unless they're really close). Don't always go for the 3 shot kill, a 4 or even 5 shot kill I fine with it. It works best against shotgunners that rush you so you might want to go into supremacy. And fire slower the further away someone is. Hope this helped. Edit: also if you still want help for the rest of the quest, I'm free on Saturday at 5. (Melbourne Australia time)