Largest of the experimental cartridges made by H.W. Gabbet-Fairfax for a Mars semi-auto pistol, in all probability between 1895 – 1903. These cartridges were to be submitted for military trials but were ultimately not successful. The main reason of its failure was in the complexity of the gun, which meant too many parts that needed fixing in the field. The gun also had substantial recoil and together with the long travelling distance of the moving parts made it prone to stoppages. (Erlmeier, Brandt Ref. 449)