ok guys i have made my cannon have a lot more power so decided it needed to be in a tower,  also please note i did not copy anyone when building this cannon i worked this out on my own, the cannon can fire over a distance of 250 blocks away a big step up from my frist one that did 50 - 55 also this cannon has a room where you sit and fire your gun its very cool lol have fun with this and dont forget to credit me as in yahgiggle as the builder.