There are two Cartridge Stores in the 6-Inch QF Gun Magazine. Only the ones opposite as you enter the Magazine (1 to 6 in the photos below) are on the original plan. The other one must have been added just before, or during construction to increase capacity from the planned total of 600 Cartridges.
RIGHT: The now vanished remains of a Ventilator Shaft from the inland Cartridge Store. A revolving cowl would have once topped this. The cowl would rotate in a breeze or wind to create a movement of the air in the Cartridge Store below.
Propellant charges were passed out of hatches in the thick walls of the Cartridge Stores to the men working on the hoists at each side of the Magazine. The walls were thickly built to minimise the effects of any explosion occurring in the Magazine.