This TNT cannon shoots 4 ammunition how ever far you want it too. It is very simple and you could even build one in survival! Feel free to change anything to it. You could even make it an 8 shot. Materials- Some blocks A bit of redstone A button Some repeaters A bucket of water And a slab Make sure you don't fill the water block! If you do then your just making a self destruct bomb not a cannon :) but if you aren't satisfied then feel free to blow it up.