 On either side of the terreplein , wide of the 64 @-@ pound guns , are two small rooms known as the expense stores . They were used for ready @-@ to @-@ use ammunition for the adjacent guns , except for armour piercing shells which were stored in the rear @-@ defence wall 's <unk> . Between the 64 @-@ pounders and the 10 " gun positions are two raised observation platforms set into the structure for gun commanders to spot the fall of outgoing shells . <unk> was either performed from here or from a ranging position set in the sand hills to the fort 's north . Between the 10 " guns is a T @-@ shaped loading gallery that draws shells and gunpowder via a hoist system from the magazine below . Either side of the gallery was installed the Armstrong mechanical loading systems for the 10 " guns . These mechanical systems proved unsuccessful and were removed in the 1890s , though the southern one has been reconstructed . The magazine is accessed from the manning parade and is directly beneath the 10 " gun loading gallery . Voice pipes and hoists originally installed have been removed but their remains are visible . 
