If firing 16,000 rounds a second just isn't enough, Metal Storm also makes a multi-shot accessory under barrel launcher, or MAUL for fans of acronyms. Using MAUL you can fire shotgun rounds or grenades the same way an M4 or M16 rifle does.
The ironic thing about the Metal Storm lies in the place where it's made. Australia has some of the most strict gun laws, but they manufacture one of the most deadly weapons in the world. Whether or not they choose to use this technology for military or commercial applications, it's definitely allowing the weapons industry to take dramatic leaps forward.