<prompt> FG, FFG, FFFG...used to describe: PGI May 2011PrimerCartridgeBlack gunpowderWadding  <response>: Ans: C Black gun.. FG, FFG, FFFG... are used to describe the size of grains of black gunpowder.Gunpowder used in FirearmsBlack PowderQ It consists of Potassium nitrate 75, Charcoal 15 Suiph ur 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, CO N2, H2S, H2, CH etc., alt at a very high temperature.Smokeless powder It consists of nitrocellulose guncotton or nitroglycerine nitrocellulose double-base. Triple base powder consists of nitrocellulose, nitroglycerine nitroguanidine.They produce much less flame smoke are more completely burnt than black powder.Semismoke less powder It is a mixture of 80 black 20 smokeless powder. 