The old magazine, or the artillery building as it was also called, was divided into two halves with a height of 3 and 4 floors respectively. The ground floor houses “Artillerie Tyghuset”, a storage room for the artillery in the east end and large powder magazine in the western part.

The second and third floors were occupied by grain warehouses and the “Artillery Rust Chamber”, that is, a weapons depot, where the fortress soldiers go to retrieve bullets, gunpowder and other equipment required when the fortress needed defending.

The elevated 4th floor closest to ‘Mors mössa’ or ‘Mother’s hat’ is set up with cannon batteries for firing towards Hisingen in the south. In the floor there is a grid covered opening to an underground shaft. From here, corridors lead under the courtyard and south under the bastion Stora Våghals. They are intended as sewer drums but also seem to be used as a payment.