It was one of the first breech-loaders: shell and gunpowder propellant were loaded through the gunner's end of the barrel, rather than through the muzzle as in previous guns, allowing a higher rate of fire.

The shells were coated with lead, which engaged spiral grooves cut inside the barrel ("rifling") and caused the shell to spin rapidly in flight and hence imparted far greater accuracy and range than previous guns.

The barrel was of wrought iron, "built up" of a tube with additional layers heated and then shrunk over it as they cooled.

The Victorian Government purchased 6 more guns in 1864 to equip its horse artillery; one of these is restored and displayed at the Australian War Memorial in Canberra.

Captain Mercer again led this battery in the Second Taranaki War until he died leading an unsuccessful attack on a Maori redoubt at Rangiriri in November 1863.