Sniper Shooting
Sniper shooting equates to precision shooting at extremely long distances. Snipers often rely on the ranging marks, also known as "mil-dots," on their scope reticles to accurately gauge the distance of their target and the required compensation for bullet drop. Snipers must also take into consideration such factors as the wind and temperature on the characteristics of the bullet.
Mil-Dot Scopes
Mil-dot scopes are used by snipers to accurately determine the range to target in meters, by using a simple algebraic formula. To determine the range you must know the target height in meters and have counted the number of range marks from the bottom of the target to the top; you must then divide the target height by the range mark count and multiply the answer by 1,000; your answer is the range in meters. For example, if your target is two meters high and your count is one then your equation would read: 2 ÷ 1 = 2 and 2 x 1000 = 2,000. Your target range is 2,000 meters.
Tactical Shooting
Tactical shooting may include targets that need to be acquired quickly and accurately. Short to medium range tactical scopes are designed for this purpose. Short range tactical scopes can include red dot scopes which provide no magnification but allow the shooter an easily identifiable aiming reference point. Typically, tactical scopes are practical for targets up to 600 meters.
ACOG
The Advanced Combat Optical Gun sight features reticles that are calibrated for ranges of 100 to 600 meters using the scope's ranging marks. These marks are designed to allow a shooter to reference a target of approximately 19 inches wide --- the average distance of the shoulders on an adult male ---to quickly adjust his aim without having to figure out the range.