Western Redoubt was also know as Fort William and together with Fort Albert, helped protect the land approaches to Fort Victoria. Fort William was similar in design to Fort George, except that the Western face was scarped to make a steep cliff about 300 feet long. The intention was to mount four 24-pdr guns on this escarpment or epaulment or gun bank. This is very similar to the scarping that was done on the Northern Lines in Gibraltar.
An additional four 24-pdr guns covered the other faces. In 1852 it was recommended that four 32-pdr SB guns be mounted on the roof of the Tower (keep) of Fort William. As with Fort George, the central keep was surrounded by a dry ditch with counterscarp galleries to protect it.
Construction of the Fort continued in the 1850s, but by 1869 had still not been armed. In a report by Chapman on the Defences of Bermuda in 1869 it was recommended that Fort William be converted to a magazine. Again nothing seems to have been done until the 1880s. An armament return from 1877 (TNA WO 28/348) does not even list Fort James (Western Redoubt).
The exact dates that this conversion of Fort James to a gunpowder magazine are not known. The dry moat had a roof built across is about the level of the second storey. The old moat and the roof were then filled with rubble. In 1890 a new access tunnel was built into the magazine from the base of the scarped escarpment.