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!

Finally, the Brits come up with something you can use.

You see, this guy doesn’t like to get dirty, doesn’t like to get a sore back, and doesn’t seem to mind pointing a shotgun directly at the ground and firing it, putting himself and his workmates in danger.

But, it is a plausible method for removing undesired plants.  (Just don’t try this at home, kids)