It is a tnt cannon but a more powerful one, can shoot multiple tnt. Range about a 100 blocks long. If cannon is build on a higher height and the power is increased the range can improve another 50 blocks long or so. Destroyed at least few of my redstone creations. So basicly this is one hardcore cannon. Cannon sometimes will be blown up due to some misplacing of tnt or maybe redstone repeater. I tried taking a screenshot of the cannon shooting multiples of tnt but the tnt doesn't show. I may post this word save on pmc.