<prompt> Fg, FFg, FFFg used to describe: PGI June 2007PrimerCartridgeBlack gunpowderWad  <response>: Ans. C Black gunpowder FG, FFG, FFFG ... are used to discribe the size of grains of black gunpowderQGunpowder used in FirearmsBlack PowderQ It consists of Potassium nitrate 75, Charcoal 15 Sulphur 10 Pnemonic - PCS in decreasing percentage It is designated as FG, FFG, FFFG, etc., depending on size of the grains. More the no. of Fs, the finer are grains the faster the burning. The powder grains are black, coarse or fine, without any particular shape. It burn with production of much heat, flame smoke. The gas consists of CO. CO2 N2, H2S, H2, CH4 etc., all at a very high temperature.Smokeless powderQ It consists of nitrocellulose guncotton or nitroglycerine nitrocellulose double-base. Triple base powder consists of nitrocellulose, nitroglycerine nitroguanidine.They produce much less flame smoke more completely burnt than black powder.Semismoke less powderQ It is a mixture of 80 black 20 of smokeless powder. 