When the Neptune-class ships were cancelled in 1946, the gun was redesigned to be mounted in pairs on the new and complex Mark 26 dual purpose mounting and gun turret designed for rapid automatic fire on the projected Design Z (Minotaur-class) cruiser.

These were to be the first British 6-inch guns in over sixty years to use brass cartridges instead of bagged charges.

By the time the first two experimental weapons had been completed in 1949, the Minotaur-class had been cancelled, and after some time it was decided to use the N5 gun (as the Mark V had been redesignated) with the Mark 26 mounting on the Tiger-class cruisers, whose hulls had been built during the war and had since been totally redesigned.

[citation needed] In April 1957, Cumberland sailed for the Mediterranean for firing trials in the course of which she expended 645 6-inch rounds.

The weapon system gained a reputation for unreliability and difficult maintenance, however the main problem was the number of technicians required to keep the guns operational.