In military and firearms contexts, milliradians are used to measure the angle subtended by a target at a given distance. This allows for precise adjustments when aiming weapons or calculating bullet drop and windage. The use of milliradians provides a standardized and consistent method for making accurate adjustments, regardless of the distance to the target.
In surveying and navigation, milliradians are used to measure horizontal and vertical angles. This is particularly useful in geodetic surveys, where precise measurements are required for mapping and land surveying purposes. The use of milliradians ensures accuracy and consistency in these measurements, allowing for precise calculations and mapping of the Earth's surface.
Milliradians are also commonly used in optics, particularly in telescopes and binoculars. They are used to measure the field of view and to make adjustments for range estimation and target tracking. The use of milliradians in optics allows for precise and standardized measurements, ensuring accuracy in various applications such as hunting, wildlife observation, and long-range shooting.
In military settings, milliradians are often used to calculate the distance between a target and the shooter, as well as to determine the necessary adjustments for elevation and windage. The advantage of using milliradians lies in their ability to easily translate angular measurements into linear measurements, making them highly practical for estimating range and making accurate adjustments.
To convert milliradians to other units of angular measurement, such as degrees or minutes of arc, a simple conversion factor is used. One milliradian is equal to approximately 0.0573 degrees or 3.44 minutes of arc. Conversely, to convert degrees or minutes of arc to milliradians, one can multiply the value by approximately 17.45 or 0.29, respectively.
The milliradian ('mil') was first used in the 19th Century by Charles-Marc Dapples, who was a professor at the University of Lausanne. At the beginning of World War I, France started experimenting with using millradians on artillery sights instead of decigrades (circle/4000). They were used by France alongside decigrades during World War I. The United States, who copied many French artillery practices, also adopted mils.
One finger width at an arms length is approximately 30 mils wide. A fist is approx. 150 mils and a spread out hand is approx. 300 mils.