Counter-sniper tactics have evolved in sniper warfare to reduce the effectiveness of snipers.
Reducing the risk of damage
During the stalking phase of their attack, a sniper will, if time allows, try to identify high-value targets, such as other snipers or Senior officers and NCOs. They will do this by closely observing the behavior of the people in front of them. The intention is to identify who is in charge and then prepare to fire at them. It naturally follows that leaders should attempt to blend into the background by avoiding anything that distinguishes them from the most junior soldiers and attracts the interest of a sniper. In order to reduce a sniper's ability to damage the chain of command, doctrine and equipment need to prevent any observable "leadership" behaviors and signs. Insignia, e.g. rank insignia, should be subdued (i.e. dark or black as opposed to bright colors), camouflage colors on battledress, battledress identical for all ranks, military servants and rank-based luxuries (like saluting) avoided in forward areas, and commands and instruction should be given discreetly. Additionally, other acts such as looking at maps, using a radio, pointing authoritatively, abstaining from menial tasks and other forms of body language can betray an officer's rank.
Locating an attacking sniper
Because snipers use camouflage, choose their firing positions carefully, and often attack from long distances, they are difficult to locate. Gunfire locators have been developed to do this. These may sense a variety of signatures including:
the shock wave from a supersonic bullet
the muzzle flash and sound
the heat of the bullet in flight
reflections from the telescopic sight
When the trajectory of the bullet can be sensed, backtracking can be done to calculate the sniper's location. Sensor techniques are often used in combination to improve detection and eliminate false alarms.
Sniper vs. sniper
A friendly sniper is generally the most effective counter-sniper tool. With similar training, knowledge of the surroundings, and equipment, the friendly sniper can offer advice to the squad, enhanced searching capability, and combat the enemy sniper directly. When told what to watch for, the squad can also act as additional eyes and ears for the friendly sniper. Aside from watching over the squad, the friendly sniper also has the option to detach and engage the enemy sniper. Without any outside help from the squad, the respective skills of each sniper play a significant role in determining victory. The enemy sniper's skill can also be determined by the precision of their shots.
Triangulation: technique at two or more locations can more accurately identify the position of a sniper at the time of firing.
Sound delay ("crack-bang"): The enemy's supersonic bullets produce a sonic boom, creating a "crack" sound as they pass by. If the enemy's bullet speed is known, their range can be estimated by measuring the delay between the bullet's passing and the sound of the rifle shot, then comparing it to a table of values. This is effective at distances of up to only 450 metres; beyond this, the delay continues to increase, but at a rate too small for humans to distinguish accurately. Also, in urban areas, the sound can give inaccurate results because the buildings in the area can relay false sound directions. Detector: A 'sniper detector' system, named Boomerang, was developed through DARPA and can determine the bullet type, trajectory, and point of fire of unknown shooter locations. The system uses microphone sensors to detect both the muzzle blast and the sonic shock wave that emanate from a high-speed bullet. Sensors detect, classify, localize and display the results on a map immediately after the shot. The system sensors are usually mounted on a vehicle. The United States military is also funding a project known as RedOwl, which uses laser and acoustic sensors to determine the exact direction from which a sniper round has been fired. The RedOwl system has been tested on the PackBot robot from iRobot Corporation.
Counter-attacking the sniper
Once a sniper's position is known or suspected, other options follow: