Explosively formed penetrator

Wide angle cones and other liner shapes such as plates or dishes with apex angles greater than 100 do not jet, but instead give an explosively formed projectile or explosively formed penetrator (EFP) (Fig. 7.6). The projectile forms through dynamic plastic flow and has a velocity of 1-3 kms . Target penetration is much smaller than that of a jet, but the hole diameter is larger with more armour back-spall. 

E) Bullet Impact Test Described by Colver. In the test briefly outlined by Colver(Ref l,p 647), the explosive is packed in cases which are arranged in a longitudinal row at various distances from a rifle. The minimum distance at which an expl detonates is noted as are the number of shots fired, the thickness of the layer penetrated and the velocity of the bullet. The shorter the distance and the larger the number of required shots to cause detonation, the less sensitive is the expi. Loosely-packed expls are usually more sensitive than those packed in cartridge form... 

Camauflet. When a missile has penetrated so deep ly into the ground that no surface effect results from the expln, but instead a rough spherical cavity is formed be low ground level, the cavity is called camouflet. This term is also applied to the explosive that makes such cavity (See also under Blast Effect in Earth)... 

The water resistance of partly water - soluble, powder-form explosives (e.g. ammonium nitrate explosives or blasting agents) can be improved by the addition of hydrophobic or gelling agents. If e.g. - Guar Gum is added, the water entering immediately forms a gel which blocks the penetration of more water. 

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