A sniper uses precisely aimed gunfire to kill at a distance, usually in excess of 100yds (approx. 100M).
Russian doctrine uses snipers for long-distance suppressive fire and targets of opportunity, especially leaders. During World War II Russians found that military organizations find it hard to replace experienced non-commissioned officers and field officers in a war. Personnel selection, training, and doctrine can improve the cost-effectiveness of the expensive, delicate sniper rifles to levels comparable to a conventional assault rifle. Additionally, sniper duties fit women well, since good snipers are patient, merciless, avoid hand-to-hand combat, and need higher levels of aerobic conditioning than other troops.
U.S. doctrine uses snipers in two-man teams attached to companies or brigades for anti-sniper missions, civil pacification, assassination, scouting and surveillance. U.S. snipers are usually far more highly trained than others, but doctrine limits their usefulness to small unit commands, the bread-and-butter of the Army.
The crucial item is good training. A well-trained sniper can compensate for poor equipment. A good sniper can reliably place bullets in a 30cm circle at 300yds in all weather at all angles. Training selects personnel for talent, and then trains them over a period of several months of daily shooting with diverse ranges, angles and weather, especially winds.
Armorers adjust sniper rifles to have a controlled distance (headspace) between the chamber containing the round, and the start of the barrel. This prevents bullet deformation and wobble as it enters the barrel.
Most rifles include light-weight hammers and firing pins (sometimes of titanium), and stronger springs to reduce the time that can elapse between the trigger release and the bullet exit. Armorers carefully adjust the trigger sears for a moderate, precise release point and force.
Sniper rifles generally have free-floating barrels that do not touch the stock, and therefore cannot be deformed as the stock expands or shrinks. Some have heavy "bull" barrels to reduce the movement circle caused by unavoidable hand-trembling. Good rifle barrels also have precision rifling and boring. Some snipers claim certain barrel alloys (the low shrinkage steels used in watch springs and sextants) change "zero" less with temperature. Further, some barrels are cryogenically heat-treated to reduce crystallization changes at normal temperatures. It's common to adjust a small weight (often a flash supressor) on the muzzle end to control barrel resonances. One company even sells carbon fiber barrels that weigh only one third of steel barrels. This helps a sniper lugging a .50 calibre rifle over mountains.
Most snipers shoot match-grade military ammunition. Some build their own from components to more precisely control the load and bullet shape. Bullets are hard, heavy, and very aerodynamic. Powder loads are only moderate to avoid stretching the gun.
Sniper sights generally contain ranging aids based on the size of human body parts, especially the head (30cm) and trunk (50cm). They usually also contain windage calculation aids. Suprisingly, some sights have quite-low fixed magnification, as low as 3x. In these cases, the sighting aids will be a set of curves in the field of view. Other sights are variable power scopes with ranging and elevation aids. These aids are helpful, but training is more important. Historic military sniper rifles used to include basic, but adjustable "iron" sights in case the scope was damaged or got foggy. Modern shock-mounted dry nitrogen scopes have been far less fragile, and many modern sniper rifles no longer have iron sights.
At distances over 300yds, snipers usually attempt body shots, aiming at the chest and depending on hydrostatic shock to make the kill. At lesser distances, snipers may attempt head shots to assure the kill. In instant-death hostage situations, police snipers shoot for the cerebellum, a small knob just behind the spinal cord at the base of the brain. It controls voluntary movement.
To perform suppressive fire during an assault, a sniper locates an enemy firing loup, times the appearance of the enemy, and shoots the enemy through the head over his own sights.
To perform suppressive fire to cover a retreat, a sniper positions his redoubt with a view to a large open space. When a pair of squads attempts a crossing, the sniper disables one person, preferably a leader. Most often this is a hip shot, possibly followed by a jaw shot to prevent effective instruction. When the squad attempts a rescue, the sniper uses rapid fire, aiming for the trunks of enemy soldiers to kill as many men as possible with hydrostatic shock. A prudent sniper leaves the area at this point, anticipating the normal flanking attack that follows. A brave or desperate sniper may ambush one of the flanks.
To perform civil pacification, sniper-suppression, and intelligence a sniper or pair of snipers will locate themselves in a high, concealed redoubt. They will use binoculars or a telescope to identify targets, and a radio to provide intelligence. They will then shoot according to their rules of engagement. In severe civil unrest, snipers may be instructed to kill any person carrying a weapon and not in a friendly uniform.
A sniper identifies targets by their appearance and behavior. Snipers shoot people in high-rank uniforms, or that talk to radiomen, or that sit as passengers in a car, or who have military servants, or that talk and move their position more frequently than others. If possible, snipers shoot in descending order by rank, or if rank is unavailable, they shoot to disrupt communications.
With heavy .50-calibre rifles, snipers can destroy equipment. Snipers can shoot turbine disks of parked jet fighters, missile guidance packages, expensive optics, or radar sets. Snipers on hill-tops can often shoot down scout helicopters lurking below a ridge-line. A related use is to shoot locks or hinges instead of using an door-opening charge.
Snipers use deception, in the form of camouflauge, unusual angles of approach, and frequent, often slow movement to prevent accurate counter-attacks.
The most effective response to a sniper is a flanking pincer by a pair of squads, through cover, or at least concealment, driving the sniper toward the group containing his targets. This decreases the chances that he will find a stealthy, speedy escape route.
Another effective tactic is to use a sniper to kill a sniper. This often results in a sniper duel, in which the most highly trained sniper wins. The duel effectively distracts the sniper from his mission. This usually favors U.S.-style elite sniper forces.
Doctrine and equipment need to prevent observable "leadership" behaviors and signs. Insignia should be low-observable camouflauge colors on camouflauge, battle-dress identical for all ranks, military servants and rank-based luxuries avoided in a forward area, and commands and instruction should be given in stealthy ways.
Valuable assets should be parked in sand-bagged redoubts until they are launched, a prudent tactic anyway to prevent damage from fragments.
Attitude to snipers
Generally snipers are isolated even from soldiers of their own army by the dislike the ordinary infantry have for this type of combat. During World War II captured snipers were often shot out-of-hand by their captors.
It should also be realised that a psychopathic or sociopathic personality is often seen as necessary for an efficient sniper as, despite the image presented in books and films, most soldiers are not keen on killing (or being killed).