18-pounder ammunition was a fixed round (i.e. the shell and brass cartridge case were loaded as a single unit, much like a large rifle cartridge), and fitted with a nose fuze. The normal service round was "Full Charge", a "Reduced Charge" round was available for training. Double base propellant (nitroglycerine and nitrocellulose) was used, Cordite Mark 1 was the standard propellant when the gun was first introduced into service. By 1914, this cordite had been replaced by Cordite MD. During the First World War this was replaced by a revised formulation that was easier to produce called Cordite RDB.