U.S. Department of Defense 
Counter Sniper Handbook – Eliminate the Risk with the Official US Army Manual [EPUB ebook] 

Counter Sniper aims to reduce the damage caused by a sniper, which can often be very harmful. The individual who shoots at police, firemen, soldiers or citizens is certainly dangerous. In order to counteract, it is necessary to train individuals whose knowledge and skills fall within the description of a sniper, but who are known as Counter snipers. This handbook provides the crucial information in the selection of the right equipment, preparation, training, and the decisive actions of the counter sniper. Content: Ammunition Rifles Sights Noise and Muzzle Flash General Notes Trajectory of 222 Cartridge Description of Epoxy Impregnation of Stock Firing Positions Typical Countersniper Situations Suitable Countersniping Equipment