As of right now, the dwarven multicannon is not working like it should. If you set your cannon, you place it diagonally to the north-east.
As an example, in the brine rat cavern (Dungeon teleport > brine rat cavern) you can see the recommended cannon spot. (Runelite plugin). On this game there is no way you can put your cannon in that little room.
Also the runelite plugin doesnt keep track of how many cannonballs there are in the cannon.
There are multiple slayer tasks that would be helped if this bug was fixed.
Thanks for reading!