<prompt> Double base smokeless gun powder contains the following elements:Nitrocellulose and nitroglycerinePotassium nitrate and nitroglycerinePotassium nitrate and leadNitrocellulose  <response>: Smokeless powders: They produce much less flame and smoke and are more completely burnt than black powder. Three types; Gun cotton: Consists of nitrocellulose Double-base powder: Consists of nitroglycerine and nitrocellulose Triple base powder: Consists of nitrocellulose, nitroglycerine and nitroguanidine Semi-smokeless powder is a mixture of 80 of black and 20 of the smokeless type. Ref: The Essentials of Forensic Medicine and Toxicology by K S Reddy, 27th edition, Page 188. 