mil-dot is derived from the metric system of angular measerment now used by hm forces-: hope these definations help
1
milliradian - a unit of angular distance equal to one thousandth of a radian
angular unit - a unit of measurement for angles
microradian - a unit of angular distance equal to one thousandth of a milliradian
radian, rad - the unit of plane angle adopted under the Systeme d'Unites; equal to the angle at the center of a circle subtended by an arc equal in length to the radius (approximately 57.295 degrees)
2
The Mil-dot reticle was originally developed for the millitary for range-finding purposes. Each dot on the Mil-dot reticle represents 3.6 inches at 100 yards or 36 inches at 1,000 yards. Although these ranges are well outside the ability of most airguns, the distances can be scaled down to provide a very effective reticle for airgun use. Many airgunners swear by the Mil-dot reticle and through experience have developed a natural understanding of what each dot represents at a given range.