The Vietnam War marked the first time that the U.S. military brought together trained snipers, custom rifles, telescopic sights, special ammunition and sound suppressors, and employed them successfully in combat. This work focuses on a small but significant aspect of modern military history: the army sniper program, the fielding of the XM21 sniper rifle and the Adjustable Ranging Telescope, and the combat application of sound suppression devices for rifles and special carbines.