As my second minecraft instructable I will be showing you how to make an extremely powerful TNT cannon, which can fire a single TNT ammunition over a distance of 300m.
To make this you will need: redstone dust, any kind of solid block (I used granite), repeaters, a button, a bucket of water, any kind of half slab and TNT.
Step 1: The Base
Get started with an 8 by 3 by 1 base. Now make a ring on top of the base leaving out the end block.
Now make a one block wide strip on the left side, place a half slab at the open end and a bucket of water at the closed off end as shown.
Step 3: Covering the Water
Cover the water by placing and breaking the blocks as shown.
Step 4: The Redstone
Place a button on the back of the block, then place redstone dust as in pic 3.
Step 5: More Redstone
Place 6 repeaters on the right side of the cannon with two dust at the end. On the left side, place redstone dust all the way down the side, missing out the end block.
Step 6: Firing
To load and fire it, just lay down TNT in the water and on the half slab. Now press the button and stand back.
I found that the tnt that was being fired, was being lit too quickly, so I set all the repeaters to three ticks-shown in pic 5.
Hope you all enjoyed this build as there will be many more to come:)