Fully-Automatic 12 gauge shotgun that can fire 300 rounds per minute.  Strictly for military use, but think of the fun you could snow goose hunting!

Or even better.  Our sporting clays range used to do a thing called The Flurry at the 5-stand.  It was a 2-second delayed firing of sequential stations until 30 birds was reached.  This would make that little even a lot of fun!