Iron cannonball

Iron Cannonball is a members-only item on the OSRS Grand Exchange in the bars category.

In-game examine text: "Ammo suited for a boat's cannon."

It has a Grand Exchange buy limit of 11,000 every four hours, a high alchemy value of 2 gp, and item ID 31908.

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Iron Cannonball shows an active flip setup with a margin of +1 gp and 1,112,945 trades over the last 24 hours.

At the buy limit of 11,000 every four hours, max profit per cycle is about 11.0k gp — high margin with healthy liquidity.