You're still flicking rubber bands with your fingers? My friend, please. Please take a look at this 9kg, eight-barrelled Gatling rubber-band gun. Before you say no to the $US500 price tag, watch it work in this terrifyingly soundtracked video.
The made-to-order gun can load up to 100 size 64 rubber bands and is apparently "safe enough for close-range shooting". Safe being one of those vague, relative words that gets thrown around a lot and I assume means different things in different cultures. And yes, it comes with a Maglite mounted on top. While it may not be drill-powered, it's still terrifying.