TNT Cannon. The Shot is placed adjacent to the water and next to where the Charge will be, therefore holding the water there. The following happens when the shot is lit exactly 4 sec after charge is lit: When more than one TNT falls from a vertical stack, it destroys the front end of cannon. When one or more TNT is placed after TNT 2 and is lit horizontally, it destroys front of cannon. Timing between Charge and Shot: 8 untouched repeaters, 8 fully delayed repeaters. that is 4 sec. The glitches happen at random times, it may not do this for 10 tries in a row. When the cannon fires without problems, water just runs down. The Charge's components: TNT are lit simultaneously. This is a regular TNT cannon except: the Shot is directly in front and is holding the water, the lit TNT charge is therefore next to the Shot. (the cannon is supposed to have some blocks around the charge to straighten the falling TNT as shown in the reproduction images) Water does not have to be used: if you replace the stone with obsidian or bedrock, once in a while you may get your repeaters or wires destroyed AND the TNT shot will either go too far or just a few meters. The more TNT you use at point blank to the shot, the more likely it will bug out.