With the mortar, it is essential you only load as much gunpowder as you need. 3-4 gunpowder goes on for hundreds of blocks. 1 gunpowder loaded is enough to hit most targets, but even then you might need to move it backwards.
If you craft a clock, go on a cannon and press shift, the cannon's angle will be slanted towards the direction you are looking at. This works for any cannon, and the angle is roughly visualized with a trail of glass blocks.
Nevermind the question, zaify, i just checked out the plugins page. Pretty cool plugin, I must say. I'll make an auto-reloading cannon and raze some forts.
Dj, here is the plugin's page: http://dev.bukkit.org/bukkit-plugins/cannons/pages/tutorial/
Zaify, by going into a cannon do you mean going on top of the pressure plate or the iron block and then shifting?
The plugin's been here forever. It's very simple how to make them, just ask anyone who's been on the server for a while
sorry, i know you have already heard this story but ill say it again. i didn't know this because (even though i am an old member) i was gone for a while. btw thanks for answering, ill ask around to see how to build one.