William Armstrong's innovative combination of a rifled built-up gun with breechloading had proven suitable for small cannon.

When it was applied to a 7-inch gun, it proved that the pressure caused by the explosive charge that was required to propel a 110-pound shot was too much for his breechloading system.

A metal cup on the front of the block, together with the pressure of the screw behind it, provided "obturation" and sealed the breech to prevent escape of gasses rearward on firing.

This spin, together with the elimination of windage as a result of the tight fit, enabled the gun to achieve greater range and accuracy than existing smoothbore muzzle-loaders with a smaller powder charge.

On top of each powder cartridge was a "lubricator" consisting of tallow and linseed oil between two tin plates, backed by a felt wad coated with beeswax and finally by millboard.

Now Sir William Armstrong's breech-loader is on a diametrically opposite system; nothing there confines the gas but the actual amount of labour expended in the screwing up of the breech.

[11] The abandonment of the Armstrong breech-loading design led Britain to begin a major program of building rifled muzzle-loaders to equip its fleet.

At Kagosima one vent-piece of the pivot-gun broke and a piece went up to foreyard, but no one was hurt, and it was the fault of the captain of the gun not putting the tin cap in.

[14] Although subjected to one of the fiercest bombardments of the wars, the Maori defenders were protected by anti-artillery bunkers and went on to repel the British force, inflicting heavy casualties.