British and German propellant charges differed in packaging, handling, and chemistry. The British propellant was of two types, MK1 and MD. The Mark 1 cordite had a formula of 37% nitrocellulose, 58% nitroglycerine, and 5% petroleum jelly. It was a good propellant but burned hot and caused an erosion problem in gun barrels. The petroleum jelly served as both a lubricant and a stabiliser. Cordite MD was developed to reduce barrel wear, its formula being 65% nitrocellulose, 30% nitroglycerine, and 5% petroleum jelly. While cordite MD solved the gun-barrel erosion issue, it did nothing to improve its storage properties, which were poor. Cordite was very sensitive to variations of temperature, and acid propagation/cordite deterioration would take place at a very rapid rate. Cordite MD also shed micro-dust particles of nitrocellulose and iron pyrite. While cordite propellant was manageable, it required a vigilant gunnery officer, strict cordite lot control, and frequent testing of the cordite lots in the ships' magazines.