Ballistic effect compensating reticle and aim compensation method
View Patent ↗A ballistic effect compensating reticle (e.g., 200 or 300 ) and aim compensation method for rifle sights or projectile weapon aiming systems includes a multiple point elevation and windage aim point field (e.g., 150 or 350 ) including a primary aiming mark (e.g., 158 or 358 ) indicating a primary aiming point adapted to be sighted-in at a first selected range and a plurality of secondary aiming points arrayed beneath the primary aiming mark. The method for compensating for a projectile's ballistic behavior while developing a field expedient firing solution permits the shooter to express the field expedient firing solution in units of distance, (e.g., yards or meters, when describing or estimating range and nominal air density ballistic characteristics), and velocity (e.g., mph or kph, for windage hold points).
1. A ballistic effect aim compensation method for use when firing a selected projectile having pre-defined ballistic characteristics from a selected rifle or projectile weapon and developing a field expedient firing solution, comprising:
(a) providing a ballistic effect compensating reticle comprising a multiple point elevation and windage aim point field including a primary aiming mark intersecting a nearly vertical array of secondary aiming marks spaced along a curving, nearly vertical axis, the secondary aiming marks positioned to compensate for ballistic drop at preselected regular incremental ranges beyond a first selected range for the selected projectile having said pre-defined ballistic characteristics; and said aim point field also including a first array of windage aiming marks spaced apart along a secondary non-horizontal axis intersecting a first selected secondary aiming mark; wherein said first array of windage aiming marks define a sloped row of windage aiming points having a slope which is a function of the direction and velocity of said projectile's stabilizing spin or a rifle barrel's rifling twist rate and direction, thus compensating for said projectile's crosswind jump;
(b) based on at least the selected projectile, identifying said projectile's associated nominal Air Density ballistic characteristics;
(c) determining a range to a target, based on the range to the target and nominal air density ballistic characteristics of the selected projectile, determining a yardage equivalent aiming adjustment for the projectile weapon;
(d) determining a windage hold point, based on any crosswind sensed or perceived;
(e) aiming the rifle or projectile weapon using said yardage equivalent aiming adjustment for elevation hold-off and said windage hold point, and
(f) wherein the step of identifying said projectile's associated nominal Air Density characteristics comprises: for the selected projectile, identifying a first nominal air density designation in air density units corresponding to said selected projectile's ballistic characteristics at a first nominal muzzle velocity; for the selected projectile, identifying a second adaptive air density designation in air density units corresponding to said selected projectile's ballistic characteristics at a second muzzle velocity which is higher or lower than said first nominal muzzle velocity; and identifying ammunition muzzle velocity specific nominal Air Density ballistic characteristics for said selected projectile at said second muzzle velocity.
2. The ballistic effect aim compensation method of claim 1 , wherein the step of identifying said projectile's associated nominal Air Density characteristics comprises:
providing ballistic compensation information as a function of and indexed according to density altitude for presentation to a user of a firearm, and associating said ballistic compensation information with a feature of said reticle to enable a user to compensate for existing density altitude levels to select one or more aiming points displayed on the reticle.
3. The ballistic effect aim compensation method of claim 2 , wherein the ballistic compensation information is encoded into markings included with said reticle via an encoding scheme.
4. The ballistic effect aim compensation method of claim 3 , wherein the ballistic compensation information is graphed, or tabulated into markings disposed on the reticle.
5. The ballistic effect aim compensation method of claim 3 , wherein the ballistic compensation information comprises density altitude determination data and a ballistic correction chart indexed by density altitude.