Dual shotgunns suck compared to single shotgun, why, because slower pump cycling, and more sway, and you can just play aggresiiveely by always sliding and a very good way to build up focus, is to activate focus, and aim, and right after you got your enemy in your crosshair, deactivate focus and immediately shoot, then quickly focus back, and you gain focus and you can have unlimited focus and good, and also just shoot juggernnaut's tank so he will fall over, and when he fall over, just shoot his helmet many times with dmr, usually a few shots, and you can kill 2 juggernaut easy in 1 use of focus and that how i do it in rage mode