It also helps to have the Scavenger perk on. By the time an AC130 is in the air, there should be at least a couple of spots where people have died and left blue bags around for you to re-up with.

And the Cold Blooded Perk is one of the best perks they added. If you get the Pro version, your enemy's crosshairs won't turn red and your name won't turn red either. Pretty useful when you're hiding in bushes.