When did sniping become an army unit?

Early forms of sniping or marksmanship date back to the American Revolutionary War. In 1777, during the Battle of Saratoga, colonists hid in the trees and used early model rifles which they did use to shot at British soldiers.

During World War I, it was the Germans who first had a reputation for their deadliness and efficiency where snipers were concerned. A part of it was due to the high-quality lenses that the German industry did manufacture. They also specially equipped some of their soldiers with scoped rifles that could pick off enemy soldiers