Most of the time , a sniper rifle has a telescope called a sniper scope to help the sniper see the target . There were also some instances in the early 1990s of British soldiers and RUC personnel being shot with .50 caliber Barrett rifles by sniper teams collectively known as the South Armagh sniper . In Northern Ireland , in addition to the uses listed above , a sniper was quite often a form of bait called a `` come-on '' , whereby the sniper 's position would be made obvious to a British patrol so as to draw them into an ambush in their attempt to close with the sniper .