Generally, a sniper's primary function in modern warfare is to provide detailed surveillance from a concealed position and, if necessary, to reduce the enemy's combat ability by neutralizing high-value targets (especially officers and other key personnel) and in the process pinning down and demoralizing the enemy. Typical sniper missions include managing intelligence information they gather during reconnaissance, target acquisition and impact feedback for air strikes and artillery, assisting employed combat force with accurate fire support and counter-sniper tactics, killing enemy commanders, selecting targets of opportunity, and even destruction of military equipment, which tend to require use of anti-materiel rifles in the larger calibers such as the .50 BMG, like the Barrett M82, McMillan Tac-50, and Denel NTW-20.