A number of largish guns were promptly set up on Taiaroa Head among earth and stone ramparts. Central among them was an Armstrong Disappearing Gun, with a five-ton barrel and capable of firing 100 lb 6-inch shells a distance of 8800 yards. This impressive armament was mounted in a chamber just below ground level, from whence it could be aimed. After it rose up and fired, the recoil would reset it in its below-ground position ready for reloading. Tunnels gave access to the gun and its ammunition.