His method of conversion was as follows: The cast iron gun was bored out, a loose barrel of coiled wrought iron strengthened at the breech end by a coiled 'B' tube and closed by a screw cap, was fitted into the gun as a close mechanical fit. The barrel was secured by a collar screwed into the muzzle and prevented from turning by a plug screwed through the gun near the breech.

It was then rifled after which a few heavy proof rounds were fired to expand the barrel into close contact with the exterior case. A tell-tale hole provided to indicate any failure is generally found under the cascable.

Palliser's system saw limited service in coast and naval roles, as the old SBML guns converted were too short to achieve the longer ranges being demanded in the 1870s. Conversions were limited to 64-prs and heavier. An interesting example of the gun may be seen at the Army Memorial Museum, Waiouru. The New Zealand Government bought eight of them in 1885 after they had been declared obsolete by the Royal Navy in 1879. They probably got them cheap!