U.S. Department of Defense 
Accurate as an American Sniper – US Military Handbooks [EPUB ebook] 

The sniper has special abilities, training and equipment. His job is to deliver highly accurate rifle fire against targets, which cannot be engaged successfully by the regular rifleman because of range, size, location, fleeting nature, or visibility. This e-book provides information needed to become an excellent shooter. It is organized as a reference for snipers and it leads through the material needed to conduct sniper training. Subjects include equipment, weapon capabilities, fundamentals of marksmanship and ballistics, field skills, mission planning, and skill sustainment.