OSRS Dwarf Cannon Calculator

How the cannon fires

The barrel turns an eighth of a circle every game tick, so it faces all 8 directions every 4.8 seconds, 750 turns an hour. Facing each direction it can fire one cannonball into a triangle of tiles in front of it, which makes 6,000 cannonballs an hour the most it can use. A monster standing beside the 3 by 3 cannon, or one tile out from its corner, is in two of those triangles and takes two shots a turn; a monster bigger than one tile is aimed at by its south-west tile.

In a multicombat area it shoots at every monster in range, so more monsters means more of the eight directions have something to hit. In single combat it shoots only at the monster attacking you, once or twice a turn while that monster lives. If you safespot in single combat and nothing is attacking you, it fires at every monster in range as it would in multicombat. It holds 30 cannonballs, and more once you claim Combat Achievement rewards: 35 from the Medium tier, 45 from Hard and 60 from Elite.

After 25 minutes set up it breaks and stops firing, however many cannonballs it has used. Clicking it repairs it. Left broken for another 10 minutes it disappears, and Nulodion gives it back for free with the cannonballs that were in it. Some bosses, among them the King Black Dragon and the Kalphite Queen, destroy a cannon set up near them; Nulodion replaces that one for free too. The item despawn timer can count down to the break and the decay for you.

Accuracy and damage

The cannon always hits up to 30, or 35 with granite cannonballs, and every point of damage gives 2 Ranged experience and no Hitpoints experience. Its accuracy is borrowed from you. With a ranged weapon it uses your ranged accuracy, with your Ranged level, ranged attack bonus and ranged prayer; with a melee weapon your Attack level and the stab, slash or crush bonus of the style you have selected, with melee prayers. Unarmed counts as crush. A powered staff such as the trident uses your ranged accuracy if your Ranged level is higher than your Attack level and your melee accuracy if not, and any other staff counts as a melee weapon even while it autocasts. Boosts that work on every monster count, such as crystal armour with the bow of faerdhinen; boosts that need something of the target, such as a slayer helmet on task or a salve amulet against the undead, do not. The monster defends with its heavy ranged defence. The hard Kandarin Diary box makes your enchanted bolts fire their effects more often, and the achievement diaries calculator lists every task that tier needs.

Dinh's bulwark stops the cannon from firing while it is in its defensive mode. The DPS calculator works out your own attacks against any monster with every option, and the max hit calculator shows how your gear adds up.

Cannonballs

The dwarf multicannon fires only steel and granite cannonballs. The bronze, iron, mithril, adamant, rune and dragon cannonballs that came with Sailing are for the cannons on a boat. Steel cannonballs need 35 Smithing: an ammo mould makes 4 from a steel bar at a furnace for 25.6 experience, about 540 bars and 2,160 cannonballs an hour. The double ammo mould from the Giants' Foundry makes 8 from 2 bars in the same time. The Smithing calculator prices making them to your goal.

A granite cannonball is a steel cannonball coated with granite dust, which needs 50 Smithing and gives no experience. The dust drops from the Grotesque Guardians (75 Slayer) and the Mad Angel (62 Sailing) and cannot be traded, so a granite cannonball is priced as the steel one it is made from. It raises the max hit from 30 to 35. With both in your inventory the cannon is loaded with granite first, and a cannon holding granite has to use it up before steel goes in.

Where you cannot set up a cannon

The game refuses to set up a cannon in these places:

And in these it can be set up but does little or nothing:

Every other monster the game makes immune to the cannon is marked when you pick it above, and its task shows no cannonballs in the Slayer table.

The Dwarf Cannon quest

You need Dwarf Cannon to set up a cannon or make cannonballs. It is a short novice quest with no requirements, started by talking to Captain Lawgof, south of the coal trucks and north-west of the Fishing Guild, and it gives 1 quest point and 750 Crafting experience. Afterwards Nulodion, at the dwarf base south of Ice Mountain, sells the four parts as a set for 750,000 coins through his dialogue, with an ammo mould and the instruction manual, or each part from his shop for 200,625. Setting it up needs a free 3 by 3 space, and only one cannon can be set up at a time.

The ornament kit

The shattered cannon ornament kit makes the cannon look like the one from RuneScape Classic and changes nothing else. It takes one kit on each of the four parts, they cannot be mixed, and the kits come back if you take them off. A lost ornamented cannon comes back from Nulodion with its kits.

Slayer with a cannon

On a Slayer task in a multicombat area the cannon does much of the damage while you keep nearly all of your own experience, which is why it is used to speed tasks up. On a single-combat task, luring the monster onto a double-shot tile doubles the cannon's damage on it. The table above works out every task a master gives with your setup, and the Slayer calculator plans which tasks to do, block and skip.