This is the schtick to shoot mooks.
When shooting only at unnamed characters, you can down several opponents in each action. You roll the dice and apply this effect against the first target, then reduce the ActionResult by two and apply this number to the second target. Continue like this until you run out of bullets or fail to hit a target.
As an alternative, you can make a quick snapshot at a single unnamed character as a 1-shot action, using your full action value. You may not use any form of complex stunt with this move, though you may use other gun schticks as normal.