FG, FFG,FFFG....used to discribe: (PGI Dec 2008)

Ans: C (B lack gunpowder) FG, FFG, FFFG .... are used to discribe the size of grains of black gunpowder.Gunpowder Used in FirearmsBlack PowderQIt consists of Potassiu m nitrate 75%, Charcoal 15% & Sulph 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 Frs, 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^, M2, H..S, H2, CH4 etc,, ail at a very high temperature.Smokeless PowderQIt consists of nitrocellulose (guncotton) or nitroglycerine Si nitrocellulose (double-base). Triple base poivder consists of nitrocellulose, nitroglycerine Si nitroguanidine,They produce much less flame & smoke Si are more completely burnt than black powder.Semismoke Less Powder# It is a mixture of 80% black Si 20% smokeless powder.Extra Edge: Type of BulletsYawning bulletQ - when bu Llet lose its gyroscopic traj ectory, it travels in an irregular fashionSauvenier bulletQ - When bulietremains embedded in body for a long time, it is encapsulated by fibrous tissue.Frangile bulletQ When the bullet breaks into multiple pieces before entering the target.Dumdum bulletQ - When the nose of bullet is sawn off/ cut, it mushrooms out on striking the target producing an entrance wound larger than the size of bullet.Tumbling bulletQ - When the bullet rotates end on end.Tandem bulletQ (Piggyback bullet) - When one bullet behind the other enters the body through the same enterance wound.Ricochet bulletQ - When a bullet alters its path due to deflection before entering the target.Karonlein shotQ When a bullet passes through skull & brain causing bursting of skull with external herniation of brain material, it is called karonlein shot