The guns were manned by members of the Wollongong-Bulli half Company. In 1946 the emplacements were filled in to ground level, leaving only the barrels and portion of the carriages above ground. In 1986 the emplacements were excavated and the guns and carriages restored by the Ordnance Factory at Bendigo, Victoria. A grant from the Australian Bicentennial Authority allowed the fort to be restored and in 1988 it was opened for the public.

This gun was originally manufactured as a 68 pounder SBML gun by the Royal Gun Factory in 1861 and converted to 80 pounder RML in 1872.

The Armstrong RML guns introduced in the late 1850s to replace the smooth bore muzzle loading guns were to prove very unpopular as the result of a number of accidents caused failure in the new breech. The muzzle loading gun was preferred however it was now accepted that the rifled gun firing a conical shell was the best way to defeat the new armoured ships now entering service.

There was neither the production capacity nor the funds to replace all existing SBML guns immediately but in 1863 Captain Palliser introduced a method of lining smooth bore cast iron guns with coiled wrought iron rifled tubes. This provided an inexpensive means of converting medium calibre smooth bore muzzle loading guns to rifled muzzle loading guns. The 68 pounder smooth bore were converted to 80 pounder rifled muzzle loading.