WO2006060007A1 - Reticule pour viseur d’arme a feu et son procede d’utilisation - Google Patents

Reticule pour viseur d’arme a feu et son procede d’utilisation Download PDF

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Publication number
WO2006060007A1
WO2006060007A1 PCT/US2004/040189 US2004040189W WO2006060007A1 WO 2006060007 A1 WO2006060007 A1 WO 2006060007A1 US 2004040189 W US2004040189 W US 2004040189W WO 2006060007 A1 WO2006060007 A1 WO 2006060007A1
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Prior art keywords
indicia
reticle
predetermined
gun
yards
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PCT/US2004/040189
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English (en)
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Thomas D. Smith
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Smith Thomas D
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Priority to PCT/US2004/040189 priority Critical patent/WO2006060007A1/fr
Publication of WO2006060007A1 publication Critical patent/WO2006060007A1/fr

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F41—WEAPONS
    • F41G—WEAPON SIGHTS; AIMING
    • F41G1/00—Sighting devices
    • F41G1/46—Sighting devices for particular applications
    • F41G1/473—Sighting devices for particular applications for lead-indicating or range-finding, e.g. for use with rifles or shotguns
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F41—WEAPONS
    • F41G—WEAPON SIGHTS; AIMING
    • F41G1/00—Sighting devices
    • F41G1/38—Telescopic sights specially adapted for smallarms or ordnance; Supports or mountings therefor

Definitions

  • This invention relates to telescopic and other optical sighting systems for use on guns and other projectile delivering systems of all types but will herein it will be described as primarily applied to telescopic sights on typical rifles. More particularly, this invention relates most naturally to a telescopic gunsight equipped with a transparent aiming reticle and a method for using that reticle on a gun but it is certainly not constrained to that specific application.
  • Telescopic gunsights often referred to as "scopes," generally contain a transparent flat disk reticle positioned in a plane perpendicular to the line of sight through the scope.
  • the reticle conventionally has a single vertical crosshair (or hairline) and a single horizontal crosshair (or hairline), which intersects the vertical hairline near the visual center of the reticle and the scope.
  • the point of intersection of these crosshairs constitutes the primary sighting point for the scope, representing site of bullet impact at a chosen (zero) distance.
  • the gunsight is most commonly moveable in vertical and horizontal directions by way of calibrated adjustment screws located on the scope exterior (internal adjustments); in some older and a few newer and new scopes, the gunsight is adjusted by devices within the scope attachment system (external adjustments). Method of adjustment has no significant influence upon reticle design or use.
  • the shooting system which is comprised of rifle, bullet type and velocity, scope and shooter is "zeroed in” so that aiming position of the reticle crossed hairlines or reticle center point coincides with point of bullet impact on the target.
  • the reticle has a series of evenly- spaced secondary horizontal hairlines that intersect the vertical hairline below the center horizontal hairline.
  • the respective points of intersection of the secondary hairlines with the vertical hairline are typically used to estimate bullet impact points at distances progressively greater than that at which the rifle was "zeroed in” with the main (center) horizontal crosshair.
  • the shooter in order to utilize these secondary horizontal crosshairs with accurate and predictable results, the shooter must know distance from gun to target with a significant degree of precision.
  • U.S. Patent 1,190,121 to Critchett discloses a reticle having a series of target-spanning rulings disposed above a baseline, the rulings corresponding to associated shooting distances. In use, the shooter ascertains which ruling above the baseline makes the most closely embracing fit on the target, thereby determining the shooting distance (target range).
  • a separate crosshair aiming point is included in the reticle for use in association with each chosen ruling above the baseline.
  • the principle of the Critchett target-spanning rulings is that certain targets are of known, or at least estimable size. For instance, it is a fairly accurate estimate that for mature deer or antelope, the distance between the top of the back at the shoulders and the bottom of the chest cavity is about 18 inches.
  • the target- spanning rulings are spaced apart such as to span a known target size at a known range. This manner of distance measurement is consistent with conventional trigonometric considerations wherein the triangle defined by the height of the target and the viewing angle through the telescope's optical system can be considered a right triangle, which accordingly establishes the length of the base line distance to the distal side of the triangle, namely the distance to the target.
  • U.S. Patent 3,392,450 to Herter et. al. discloses a reticle having a series of target-spanning circles of different diameters which correspond to associated shooting distances. Employing the same basic distance-measuring concept as
  • Critchett the shooter employs for aiming purposes, that crosshair which corresponds to the selected circle.
  • U.S. Patent 3,190,003 to O'Brien concerns a range-finding reticle for a telescopic gunsight having single centered vertical and horizontal hairlines.
  • the portion of the vertical hairline below the horizontal centerline is provided with widened bar regions extending various lengths below the centerline.
  • Each bar subtends a target of known size. By finding which widened region corresponds to the height of the target, the shooting distance is estimated.
  • U.S. Patent 3,431,652 to Leatherwood discloses a telescopic gunsight wherein the distance to the target is determined by movement of upper and lower horizontal hairlines along a fixed vertical hairline in a manner so as to bracket the target. Once bracketed, the intersection of the lower horizontal hairline with the vertical hairline serves as the crosshair aiming point. In this aiming process, the alignment of the scope changes with respect to the gun barrel, whereby the allowance for distance is achieved when the centered crosshair is sighted directly on the target.
  • U.S. Patent 3,492,733 to Leatherwood discloses a distance measuring system for a variable power telescopic sight that is pivotally moveable in a vertical plane with respect to the gun barrel upon which it is mounted. Cams within the scope and rotatable by external means achieve vertical movement of the scope so that horizontal framing hairlines will fit the target. A specialized cam must be installed into the scope for each particular type of ammunition employed.
  • U.S. Patent 3,948,587 to Rubbert concerns a variable power telescopic sight having a reticle provided with a vertical hairline, a center horizontal hairline and three horizontal framing lines disposed below the center horizontal hairline. Aiming is achieved by positioning either the center crosshair or lower crosshairs on the target, as dictated by the observed fit of the target within the framing lines.
  • U.S. Patent 4,403,421 to Shepherd discloses a telescopic gunsight having spaced apart primary and secondary reticles which are moveable relative to each other. The secondary reticle is also moveable vertically and horizontally within the plane of the reticle. The moveable two reticle system facilitates adjustments for windage and elevation. Distance to the target is ascertained by framing indicia on the secondary reticle.
  • the telescopic sights disclosed in the aforementioned prior art patents are often of limited usefulness insofar as they do not address many of the several factors that need to be considered in the accurate aiming of a rifle under field conditions. Such factors include: a) distance to target b) drop of bullet caused by force of gravity c) hold-over or hold-under aiming points d) wind drift correction e) correction for phenomenon associated with gyroscopic forces on a gyroscopically stabilized bullet (sometimes referred to as)
  • Older reticle systems often require that the shooter look away from the target in order to make compensating adjustments and almost always require complicated mental or physical manipulations. Some of these designs may render the scopes difficult or slow to use, and some require moveable mounting on the rifle, a situation which typically subjects the scope to inaccuracy after repeated use or abuse in rugged field conditions. Moreover, correct use of any of these systems always requires the shooter to manage extraordinary mental work in what can already be a stressful situation. It is proven that such additional stress is associated with decreased performance potential.
  • the present invention is embodied in a reticle design concept for a gunsight and "sticker" system.
  • the shooter can know which sticker to choose in order to automatically calibrate this reticle to measure distance to any size target, to provide precise drop compensation aiming points for specific measured ranges beyond the normal point-blank (zero) range for any bullet, to automatically provide precise aiming points compensating for cross-winds and up-hill or downhill shooting conditions, and to provide an accurate lead point aiming corrections for moving targets, thereby providing an accurate and effective method for aiming the rifle, all with relatively simple and fast mental work that does not require extraordinary effort by the shooter or any knowledge of the particular ballistic characteristics of load or gun to which this system is applied.
  • the telescopic sighting system incorporates an optical system comprised of a forward objective lens element, a rear eyepiece lens element and intervening erector lens element, the elements being protectively confined within an elongated tubular housing adapted to be affixed to a firearm, such as a hunting rifle
  • the improvement provided by the present invention comprises addition into said optical system within said housing of a transparent reticle having indicia which simultaneously provides accurately both the function of distance measuring, range-specific aiming as well as wind related and other trajectory corrections.
  • the reticle is positioned between the objective lens element and the erector lens element.
  • the indicia incorporates orthogonally intersecting center vertical and horizontal hairlines, and four (or more or less) horizontal combination range-marker and wind bar lines, which are disposed below the center horizontal hairline with very specific vertical spacings and intersecting in a bisected relation the center vertical hairline.
  • This system can also include range marker bars that intersect the vertical axis at a slight angle.
  • the purpose of this characteristic is to automatically correct for the elevation component of wind drift. It is a recognized fact that crosswinds do cause bullets to raise or drop relative to the trajectory that would occur without a crosswind.
  • This characteristic is not described in the drawings but is a recognized potential feature that can have significant value in specific applications, such as airplane and artillery sights, but is not limited to such applications.
  • Figure 1 is a side elevation view of a telescopic sight embodying the preferred type of the present invention mounted upon a gun of the type commonly used for hunting, target shooting and related practices.
  • Figure 2 is a schematic illustration of the internal components of a variable power telescopic sight of the type shown in Figure 1.
  • Figure 3 is an enlarged view showing an aiming reticle component of the sight of Figure 1 as it appears to the user of the sight.
  • Figures 4A, 4B and 4C illustrate the use of calibration grids for learning the use of the scope of this invention.
  • Figure 5 illustrates the use of the scope of this invention on large targets.
  • Figures 6A and 6B illustrate the use of the scope of this invention on a small target.
  • Figures 7-11 exemplify sighting images perceived by the shooter in various shooting situations.
  • Figure 12 illustrates the reticle depicted in the form of a decal for taping upon the objective extremity of the scope or some other handy location.
  • the left-hand Grid Line column serves as a reminder to denote the actual number of lines with which to divide into the animal's or target's outline for height measurement.
  • the upper right column, Aiming Point at level angle denotes bullet impact point for a "6 Factor" gun zeroed or sighted-in at 200 yards.
  • the grid-line center point at 100 yards the bullet impact will be 1.84 inches (about 2 inches) high, and at 200 yards the impact point will be on target (zeroed) -- 200 yards is a typical "zeroing" range for such a gun and load.
  • the lower indicia crosshairs
  • the upper center column, Aiming Point Grid Line at 45 degree Angle denotes the angle correction when shooting uphill or downhill.
  • Figure 12 illustrates the fundamental reason that this system works: Sections of significantly different trajectories forced into relative correspondence through the simple expedient of rotation and horizontal scaling.
  • FIGURE 12 (Rotation and horizontal scaling yields similar sections for all trajectory curves).
  • FIGURES 12-26 provide additional description of the present invention.
  • a telescopic sight 10, embodying this invention is shown attached by a suitable mount 35 to a gun 12.
  • the sight 10 is formed by a tubular housing 11 containing a forwardly positioned objective lens element 13, a rearwardly positioned ocular or eyepiece lens element 14, an intervening erector lens element 15, and a reticle 16 disposed between the objective lens element 13 and the erector lens element 15.
  • a positionally adjustable magnifying lens 17 is associated with the erector lens element 15.
  • the exterior of the housing 11 may be equipped with rotationally moveable features 36 for adjusting focus, parallax, magnification ratio, windage and elevation.
  • the reticle 16 is a circular, planar or flat transparent panel or disk mounted within the housing 11 in perpendicular relationship to the optical axis or line-of-sight 18 through the scope, and is positioned between the objective lens element 13 and the erector lens element 15, typically at a site considered to be a front focal plane of the optical system within the housing.
  • the reticle 16 contains fine etched lines or hairline indicia comprising a center vertical hairline 19 and a center horizontal hairline 20, which orthogonally or perpendicularly intersect at a center point 26.
  • the reticle further defines first, second, third and fourth horizontal range and aiming marker hairlines 21, 22, 23 and 24 (or other designs as may be appropriate to specific applications) respectively intersecting the vertical hairline below the center point 26 and vertically spaced apart and of sequentially increasing length.
  • Each such range and aiming marker hairline 21, 22, 23, and 24 is bisected by the center vertical hairline 19, in the present design in a horizontal manner but potentially in an angled manner as necessary to account to the vertical component of wind drift, etc.).
  • Each combination of a gun and bullet or cartridge must be initially sighted in at 200 yards, or other selected basic zero range, which depends critically upon the ballistic characteristics of the specific bullet (refer to figure 12).
  • the center point 26 then represents the basic sighted-in bullet impact point.
  • first, second, third and fourth alternative aiming points 30, 31, 32 and 33 represent sighted-in bullet impact points at distances that are a function of bullet trajectory for the specific load used.
  • the aiming points are for distances of 300, 400, 500 and 600 yards, respectively.
  • a "6-factor" gun and bullet combination is a system that produces a 6 inch drop from a "sight-in" impact zero point at 200 yards to the bullet impact point when the same combination of gun, bullet and scope adjustment settings is fired at 300 yards, using the center point 26 as the aiming point. Bullets of different characteristics and velocity (different gun and bullet combinations) will produce different "factors.” Thus the aiming points 30, 31, 32 and 33 will correspond to different distances or ranges, which the shooter, knowing the characteristics of the bullet, will take into consideration when aiming and firing.
  • the aiming points 30, 31, 32 and 33 are useful because the trajectory curves of different bullets are similar, even though the bullets travel different distances - some similar-length section of each curve, whether closer to the gun or further from the gun, will have a sufficiently similar shape to allow accurate use of this system (refer to Figure 12).
  • center vertical hairline 19 and center horizontal hairline 20 are widened to form relatively wider or heavy posts
  • the main horizontal and vertical crosshairs can be of any particular design, as might be necessary to provide the best performance in any particular application and could even be partially or folly absent as when only a central dot is used.
  • the various dimensions and spacings of the indicia on the reticle 16 are conveniently expressed as inches of subtention or angle at 100 yards, rather than the actual engraved dimensions on the reticle lens itself. Accordingly, the width of each of the posts 25 is 5.5 inches of subtention, and the width of the hairline portions of the center vertical and center horizontal hairlines 19 and 20, respectively, is 0.6 inches of subtention. The distance between the center point 26 and the innermost extremities 28 of the posts 25, that is the length of the center vertical and horizontal hairlines 19, 20, respectively, is 25 inches of subtention.
  • these specific dimensions and ratios of dimensions are not the only possible useful designs. The important issue is usefulness in the specific application.
  • the distances or width of the separation between the horizontal hairline 20 and the first, second, third and fourth range lines 21, 22, 23, and 24 below the center point 26 are 2.0, 4.8, 7.5 and 10.5 inches of subtention, respectively - but other designs are feasible for other applications.
  • marker lines are typically of equal 0.3 inch width of subtention and are typically straight and orthogonally or perpendicularly bisected by the lower half or lower portion of the center vertical hairline 19; however, other line thicknesses and non-orthogonal intersections with the vertical line are feasible and may be preferable in some applications.
  • the lengths of the first, second, third and fourth range marker lines are 4.12, 5.90, 8.32 and 9.72 inches of subtention, respectively; however, other lengths are feasible and may be preferable in some applications - the lengths specified above correspond to required corrections for a 10 mile per hour true crosswind component, which is a wind speed to which many experienced shooters can recognize and relate.
  • the "factor" for a particular gun and bullet combination is determined by sighting it in at 200 yards using the center point of the reticle. Using the same 200 yard sight center point, a group of shots is then fired at 300 yards and average drop (in inches) is measured. This figure becomes the "factor” that is used to compute vertical bullet drop, wind drift deflection, both horizontally and vertically, and gravity correction for both uphill and downhill angle correction for that particular gun and loading.
  • Bullet drop is progressively curvilinear (following a parabolic curve), and is well predictable out to about 0.72 seconds of free flight (450 yards for a .308 Winchester; 500 yards for a 30/06; 600 yards for a 7 mm Remington Magnum; and 700 yards for a 30/378; all when used with high energy maneuverability bullets — traditionally known as bullets having a streamlined shape and a relatively high ballistic coefficient).
  • Bullet drop for a 6-factor gun and bullet combination results in a 6-inch drop at 300 yards. This factor is tripled to predict 400- yard bullet drop.
  • This 400-yard drop is doubled to predict 500 yard drop.
  • 600- yard drop the 500 yard drop is doubled and ten (inches) is subtracted from that result. This corresponds to a formula used to determine the spacing of these indicia.
  • a reticle embodying the present invention having the above characteristics and dimensions, will produce sufficiently accurate shots when using the respective reticle aiming points at the determined distances. For gun and bullet combinations that have a factor other than six, center impact distances corresponding to the various aiming points must be calculated accordingly. See Table I.
  • variable magnification scopes (commonly referred to as variable power scopes) with the reticle positioned in the first focal plane (in this design, adjusting the power setting of the scope also adjusts the absolute apparent spacing between the range indica)
  • variable power scopes with the reticle positioned in the first focal plane
  • adjusting the power setting of the scope also adjusts the absolute apparent spacing between the range indica
  • FIG. 4A Use of a scope utilizing this invention for measuring target distance may best be visualized by referring to the grid line charts as shown in Figures 4A, 4B and 4C.
  • Each grid line chart consists of a series of numbered horizontal straight lines sequentially spaced an inch apart (inch of subtention at 100 yards or approximately one minute of angle) and assumed to be visibly distinct in the scope at the indicated ranges.
  • a target such as a 9-inch tall prairie dog is drawn to occupy the top nine lines of a chart, as shown in Figure 4A, and assumed to be placed at a range of 100 yards.
  • the scope is then sighted onto said 100 yard target, producing the view shown in Figure 4B wherein the top of the prairie dog is placed at the center point 26, and the bottom of the prairie dog falls between the third and fourth range marker lines, namely between 7.5 and 10.5 inches of subtention from the center point 26.
  • the bottom of the target having an actual height of 9 inches, is 9 inches of subtention from the center point 26. It is accordingly ascertained that the 9-inch high prairie dog target is located at a shooting range of 100 yards.
  • the target heights subtended by the horizontal range marker lines increase in direct arithmetic proportion to the distance of the target from the gun. Therefore, at 200 yards, the first, second, third and fourth range marker lines measure targets of 4, 10, 15 and 21 inch actual heights (rounded), respectively. At 300 yards, the first, second, third and fourth range marker lines measure targets of 6, 15, 22.5 and 31.5 inch actual heights (rounded) respectively. At 400 yards, the first, second, third and fourth range marker lines measure targets of 8, 20, 30 and 42 inch actual heights (rounded) respectively.
  • the scope can be accurately aimed by centering the appropriate indicia along the vertical hairline upon the desired location of bullet impact. For example, with a "6-factor" gun and bullet combination, and having ascertained that the target is located at 300 yards, and knowing that the main reticle center point 26 is for a 200 yard range, the next lower aiming point, consisting of the point of intersection 30 of the vertical crosshair 19 with the first range marker 21, corresponding to 300 yards, is, under ideal conditions and with a stationary target, used as the aiming point for a direct hit.
  • the drift values would be one-half the lOmph values, and a 20 mph wind would require twice the lOmph values and similarly for other true crosswind velocities.
  • Fig. 6A The sight picture for shooting at a 9-inch high prairie dog at 100 yards is illustrated in Fig. 6A.
  • the sight picture for shooting at a 9-inch high prairie dog at 600 yards with a 10 mph left crosswind is illustrated in Fig. 6B.
  • the view through the scope when shooting at a target at 500 yards is illustrated in Fig. 7.
  • Figs. 8 and 9 illustrate adjusted aiming points to compensate for 10 mph and 20 mph right-to-left crosswinds, respectively.
  • the ends of the range marker lines having the above lengths, constitute aiming points to compensate for 10 mph winds at the respective ranges.
  • Length of the range marker bars on each side of the vertical centerline are one half the total length or 2.06, 2.95, 4.16 and 4.86 inches of subtention at 100 yards respectively.
  • Magnus is to adjust l/4th the total value by sliding that point onto the target.
  • the aiming point is shown as an interpolated point left one equal wind bar (10 mph) and 1/4 above the left tip of the third range marker line.
  • the rule is to construct a "kill zone" on the target and then hold “worst and best" Magnus movement so that the bullet is aimed with sufficient accuracy to intersect the kill zone.
  • the formula or adjustment for a 60° angle shot is as follows: a. at 200 yards, raise the aiming point an amount equal to 2/3rds of the factor, or 4"; b. at 300 yards, double the 200-yard value, or 8"; c. at 400 yards, double the 300-yard value, or 16"; d. at 500 yards; double the 400-yard value, or 32".
  • the reticle of the present invention performs with each gun and bullet with the same precise degree of accuracy. The shooter is thus provided a similar but unique reticle decal for each combination. It must be stressed that the associated decals are an integral part of this system and as such, the concept of application specific decals is also part of this art.
  • a telescopic gunsight utilizing this invention is particularly well suited for shooting at moving targets. It is generally known that a deer starts running at about 12.5 mph. The distance between the reticle center point 26 and the innermost extremities 28 of the posts 25 compensates for a target moving at 12.5 mph. Further adjustments can be readily made for targets moving at other estimated speeds and angles, in direct proportion to the 12.5 mph speed adjustment.
  • the final sight picture provided by the reticle embodying the present invention corrected for range, wind, external ballistics, and target movement results in a straight line aim and shot at the target in the same manner as a point blank range shot. This enables the shooter to have much more confidence in the result and therefore to more easily achieve accurate shot placement.
  • a final point of significant value revolves around the difference between first and second focal plane reticle placement in a variable power scope.
  • the former design provides for a means of making any "factor” reticle design fit any "factor” application.
  • the disadvantage of this method is that it requires use of the variable power scope only at one specific power setting for the particular application.
  • the disadvantage of the latter method is that it requires use of a specific "factor" reticle.
  • Each system has advantages and this art covers any and all such applications.
  • the Adino is the 2nd focal plane system based upon the TDS TRI-FACTOR (PATENTED).
  • the Adino uses the first part of the Tri-Factor system as we use the original factor to establish the first zero.
  • Step 1 Zero according to the factor program using the fastest cartridge available for your rifle.
  • Step 2 Load the next heaviest bullet. Firi ng a sighter shot at RMB #3 will result in the bullet hitting low (top target- bottom left bullet hole).
  • Step 3 Hold the Crosshair of Baseline on a known geographic point - such as the horizontal timber in upper target - now turn the power ring down until the Aiming Point of the reticle overlaps or superimposes the bullet hole.
  • Step 4 Firing the next shot at the # 4 RMB target, should you have accurately lower ed the RMB marker, you will have an impact point similar to the bottom target where the bullet hit slightly right but level. In this case, this was a 600 yard target, firing a .308 168 grain match bullet.
  • the low left impact bullet hole was the result of a slight right wind and an undercorrected power advustment.
  • the fight will be settled in less than two seconds after the first shooter enters the Psychophysiological Performance State for a Gunfight which activates his Action Phase.
  • Our shooter will win if he can (1.) measure the distance, (2) react with a correct Gun Solution and (3) fire in less than one second. Bracketting - the head, dropping the bar over the head to the hostile's nose - while dropping the sear - wins evedry time.
  • a three hundred yard fight is the average longest shot for Vietnam ere snipers, the distance Carlos Hathcock killed the Cobra, the distance Zaitzev killed Thorvald and the range the A.T.F. snipers fired in support (?) of the fight at Mount Carmel. This seems to be the break point for otherwise good shots to get themselves killed in battle. Why? It looks easy and is a dead cinch at a KD range shooting in the psychopsysiological condition known as Yellow. What happens at 300? For one thing the ration of wobble area to kill zone - 1 to 3 -Js a bit harder to get just right. We miss more in Black. 300 yards in combat is not that easy. This is why we bracket the shot once more. Our shooter has only two things to work on - the same two that always work in practice. Bracket and fire.
  • TDS TRI- FACTOR System converts these hitherto "Art” items a science. Measurement uses the full top-of-head-to- belt region for two reasons;
  • the TDS TRI-FACTOR System ignores Yaw of Repose as long as its effect is negligible - in Baseline, Bl and B2, when close proximity makes saving every quarter second response time essential to life. At 500 and 600 yards, where an adjustment is necessary to keep the bullet in the kill zone, we have that extra quarter of a second to insure a first shot kill.
  • Combat is a world of its own, Fig. 1, a photo I took of the Ho Chi Minh trail exiting North Vietnam, illustrates what close proximity does to a well honed trigger finger.
  • Those bomb craters were made by Top Gun dive bomber pilots who routinely placed their bombs in a thirty foot circle - back home - without the distraction of a thousand AAA batteries opening up as we cleared the clouds.
  • Figure 2 is paying attention to business, which means when you are working up close don't clutter up your mind with non essentials.
  • the Rangers use a scope that costs around $6,000.00 and sets up everything for the shooter. When the proper inputs are made, the shooter simply places the crosshair on a moving target and pulls the trigger. Everything is computed.
  • This Tn Factor school is an independent hunter's adaptation that accomplishes the same thing with a $350.00 scope. It requires- a-little thought - but not too much.
  • This system is designed to provide the hunter a simple procedure for measuring the distance to an animal; then to quickly compute an incorporated holdover point for bullet drop, lag point for wind drift, a lead point for animal movement, and hold down point for severe uphill or downhill angle correction. That sounds like a mouthful and it does involve a little study. Since I'm not very smart I have to use fingers and some small memory work but if it works for me it will work for anyone else who managed to get through Dick and Jane.
  • the bullet is the subject of this drill, not the rifle.
  • the bullet begins to fall as soon as it leaves the muzzle of a rifle.
  • the fired bullet begins to slow down as soon as it is fired.
  • the bullet travels fast, covering the first 100 yards quickest. Since we are considering 600 yards as our maximum range, the bullet travels the last distance between 450 and 600 yards the slowest. Gravity causes the rate of drop to increase as flight time increases. Since it takes the bullet more time to travel as the speed slows, the effects of gravity and wind increase as the range increases.
  • the Tri Factor's entering argument initiates at 300 yards because the anomaly of bullet drift is broken at 300 yards and this entry point allows all the other solutions to integrate at that distance.
  • BULLET DROP The bullet is affected by gravity just like any other falling object. Hold a bullet in your left hand, hold the rifle horizontally in your right hand, fire the rifle and drop the bullet at the same time and each bullet will hit the ground at the same time. Even though the bullet is traveling fast, once it has been fired by the rifle, it falls to the ground in normal time.
  • BALLISTICS This is the science dealing with the motion and flight characteristics of projectiles.
  • the study of ballistics in rifles is divided into three categories; internal, external and terminal.
  • INTERNAL BALLISTICS concerns what happens to the bullet before it leaves the muzzle of the rifle.
  • Internal ballistics factors such as projectile length, weight, and configuration require different twists in the barrels, lands and grooves to stabilize a bullet in flight.
  • the lands rotate the bullet and give it a twist. This spin stabilizes the bullet and gives it accuracy.
  • the powder burning speed and type, weight of the charge, alignment and spring of the primer and primer type, squareness and concentricity of the brass case and neck wall, together with bullet shape and seating depth which determines bullet jump all contribute to internal ballistics and vitally affect accuracy.
  • the concentricity of the barrel and the amount it whips or vibrates during this cumulative firing sequence vitally affects accuracy.
  • EXTERNAL BALLISTICS deals with factors affecting the flight path of the bullet between the muzzle of the rifle and the target. External ballistics factors. When the bullet is launched into the earth's atmosphere its path is influenced by various forces and elements.
  • TERMINAL BALLISTICS deals with what happens to the bullet when it comes in contact with the target. Terminal ballistics concern bullet penetration and depend on the range, velocity, bullet characteristics, and target material. Rabbit or Rhino? Greater penetration does not always occur at close range with the high speed bullets because they tend to disintegrate. I personally love them because they are so accurate, but Sierra hunting bullets -just like the original Sidewinder missile - specifically require a spin and heat time before they become good killers. This is the manufacturing process which makes them accurate. Some of them require a 125 yard run to spin up to cohesive form. Another nit noi is that the exposed lead tips on bullets burn off and create an aerodynamic which is generally insignificant. Bent bullet tip deformity is another subject. The bullet trade off is for destruction rather than some insignificant increase in accuracy.
  • TEMPERATURE As the temperature rises, the bullet hits higher on the target. A 120 degree change in temperature will move a .300 magnum 180 grain boat tail bullet about an inch high at 300 yards.
  • ATMOSPHERIC PRESSURE As the atmospheric pressure rises, the bullet hits lower, in other words, the higher the humidity is the thicker the air is and the bullet works harder and is slowed down by the thicker air and it strikes lower.
  • WIND A strong wind from the rear causes the bullet to hit high while a strong head wind causes the bullet to hit low.
  • CHANGING LIGHT Changing light conditions can affect the way your rods and cones in the back of your eye “see” the target and cause the bullet to hit in different locations.
  • CROSS WIND DRIFT Unless it is severe, wind is a negligible factor out to 300 yards. The most serious effect is our ability to hold the rifle steady enough for a long range shot. Twenty mile per hour gusts during the firing sequence are more detrimental than a 12 inch drift correction. Unless you have an exceptionally strong muzzle wind which would affect the gyroscopic tilt of the bullet, the actual bullet path will not parallel the wind drift path during the first 300 yards to the target. Because of its powerful initial inertia, the bullet does not follow the crosswind precisely during this first 300 yards of travel. The crosswind bullet motion is accelerated relatively slowly, and in fact the crosswind component of the bullet's velocity never does grow to equal the crosswind velocity - but it is very close to linear from 300 yards on.
  • An easy system to use for rifle bullet correction is to take the time of flight and correct one inch for each second of free air time.
  • GYROSCOPIC EFFECT A spinning projectile from a rifled barrel is, in effect, a free gyroscope. When subjected to a twist or torque, it tends to rotate about an axis perpendicular to the axis about which the torque is exerted.
  • the front wheel of a bicycle is a good illustration of this phenomenon. If the bicycle is tipped to the right when rolling forward, the front wheel resists tipping and instead its axle rotates to the right, turning the bicycle to the right.
  • gyroscopic drift is difficult to analyze precisely because many variables are involved.
  • Drift tables which have been determined mainly from well-controlled army and navy tests, indicate that gyroscopic drift is roughly double that of Coriolis drift, and thus is also negligible for most purposes. It is interesting to note that with counterclockwise or left-twist barrel rifling, gyroscopic drift is to the left in the northern- hemisphere and more than cancels the effects of coriolis drift.
  • THE TRI FACTOR STEP ONE The object of this study is to enable a hunter to measure the distance to an animal by trigonometric triangulation.
  • STEP TWO Computing the shot applies the specific factor idiosyncratic to that particular rifle/bullet combination. Reloading tables may seem to be anomalistic, but that is not always so. There is very much consistency in the energy curve of similar bullets. We will organize all long range bullets in three common projectile groups. The study is of the bullet, not the rifle. The rifle only enters into the discussion after the proper bullet is selected.
  • BULLET SELECTION The first thing necessary is to determine the class of game you will hunt and the distance you expect to shoot. There is a minimum energy requirement most hunters accept for these. Although I have friends who take only brain shots and the guys in Alaska have recorded Grizzly Bear kills with a .22 rifle, in consideration for "one shot" kills, the following criteria seems reasonable.
  • Sectional density is the ratio of the bullet's weight in pounds to the square of its diameter in inches. Think of it this way; bullets of the same shape but with more weight in relation to their diameter will retain their velocity and energy better.
  • BALLISTIC COEFFICIENT It must have a minimum ballistic coefficient of .350. Mathematically, this is the ratio of a bullet's weight to the product of the square of its diameter and its form factor. If this is unfamiliar to you, get a handloading book and compare, for instance, the picture of a boat tail spire point bullet with a flat point bullet. The swept back nose and the angled tail section of the boat tail spire point bullet obviously allows it to push through the air with the least resistance. Thereby, it retains its speed longer because it doesn't have to fight so much air friction. The higher the number, the better the performance.
  • THE RTFLE We require an accurate rifle. Accuracy is relative to the intended target but for my purpose I'm defining accurate as one that will shoot 3 bullets into a one inch group at 100 yards. Also I am much more interested in what the rifle will do with the first bullet shot out of a clean cold barrel than I am with how it handles subsequent shots.
  • the one I use is a variation on the one I taught in fighter aircraft to determine effective firing range to anoLher airplane.
  • the circle in the center of the gunsight is 2 mils in diameter and will precisely superimpose a 2 foot circle at 1,000 feet, and an eight foot circle at 4,000 feet.
  • the Migs I was concerned with had eight foot tails. If the reticle ringed the tail I was at 4,000 feet and had to drive in closer until he was in firing range, when my reticle covered about a third of the migs tail, I was at "sighted in" range See illustration 2.
  • Illustration 3 This shows the picture of a MIG at 4,000 feet and 1,333 feet.
  • the pipper small white circle in center of gunsight
  • the pipper is 2 mills across, which is two feet at 1,000 feet and 8 feet at 4,000 feet.
  • the distance is 4,000'; if it is 1/3 rd the size of the tail the distance is 1,333 feet.
  • the illustration is for distance: not aspect angle for an aerial shot.
  • the Tri Factor system is the same The purpose is to measure the distance to a target in order to guarantee a fatal hit.
  • the object of surveying is to determine accurately the measurement of distance; which is also our concern in hunting. All measurement for distance is made perpendicular to the direction of gravity (designated as horizontal). Two types of angular measure are used throughout the world, the sexages ⁇ mal and the centisimal:
  • Illustration 4 The Tri Factor. Calibrate the reticle in minutes of angle, divide the animal's known chest measurement by the minutes of angle subtended (6 in this case) and you have the distance in yards.
  • Illustration 5 Both illustrations are of the normal duplex reticle .
  • the "pipper” is pointed out on the right side illustration and consists of the thin low wire from the intersection of the horizontal wire to the top of the post. This post top is called the “spearhead” and it should be noted that it is difficult to see in poor light.
  • the "pipper is the low thin wire
  • the "spearhead" is the point of the top of the post
  • Field of view simply means the area you can see at a particular power setting At 60 x power, you might be able to see a bird's head at a certain distance
  • the power ocular ⁇ ng is rotated to 2 X power it is conceivable the field of veiw might be so large that you could't even see the bird.
  • Our instructions will be to calibrate the scope's pipper to 6 minutes of angle (moa ) This is then the only power setting that you will be able to use the pipper as a minute of angle measuring device that will measure 6 minutes of angle Illustration 6. Minute of Angel
  • Minute of angle is a term used to discuss shot dispersion It is the standard unit of measurement used in adjusting rifle sights and other ballistic related measurements. It is also used to indicate the accuracy of a rifle
  • a circle is divided into 360 degrees. Each degree is further divided into 60 minutes, so that a circle contains 21,600 nu ' nutes
  • a minute of angle is an angle beginning at the muzzle that would cover 1 inch at 100 yards. When the range is increased to 200 yards, the angle covers twice the distance, or 2 inches The rule applies as range increases, it is 3 inches at 300 yards and 10 inches at 1,000 yards.
  • Illustration 7 Increase of shot group size Just as the distance covered by a minute of angle increases each time the range changes, a shot group can be expected to do the same. For instance, if the 100 yard group was 2.5 inches, it will be 5 inches at 200 yards and 25 inches at 1,000 yaids
  • PROCEDURE Calibrating the pipper is simple Set your mounted ⁇ flescope precisely 100 yards from the target.
  • TWs six line grid is not on the scope. It must be imagined by interpolation.
  • a military mil scale reticle allows the sniper to simply read the mark to obtain his distance We, however, have to visualize the graduation marks and interpolate them in the hunting field
  • the second Whitetail was 15" deep. Standing at 300 yards he was measured at 330 yards. The bullet, if perfectly shot, hit 4" below the hair and might have damaged the spine.
  • Target identification is a witch. Obviously, one of the things that makes it difficult is the relative size of male/female animals. Adult males can be 20% larger than the females standing next to them.
  • MEASUREMENT Divide the chest size by the minutes of angle subtended. This single figure will represent hundreds of yards or portions thereof.
  • Hint The easy way to divide is to determine the number of minutes of angle subtended, then add these with your fingers until you reach the animal's size. How? Measure the animal with your scope. Determine he is - say - 5 minutes large. Look at your fingers and start adding "5", popping up a finger 1 with each addition, "5" "10" "15” "20", until you arrive at the his size. If the animal is 20 inches thick you will have four fingers sticking up when you hit 20. Sound strange? Try this measurement sometimes when you decide it's 4 and a half and try to do it in your head while a Kurd guide is screaming "shoot shoot. He is going to get away.”
  • PROCEDURE Sight in at 200 yards. Then fire at 300 yards with the same dead center hold you used at 200 yards. Measure this drop at 300 yards in inches. With a .300 Weatherby it will be about 6 inches. This Factor is now SIX. This drop measurement, "SIX” is called The Factor. It will tell you all you need to know for both bullet drop and wind drift to 600 yards for your .300 Weatherby.
  • My Crown grade .300 Weatherby magnum shooting a 200 gr. nosier partition bullet (M. V. 3075 fps, 16 FPS variation, S.D .301, B.C. .481) drops 6" from my rifle at 300 yards when sighted in at 200 yards dead center.
  • the 6 mm bullet is the low end of the scale for using my system.
  • the caliber I start with is the 120 grain 25/06. It has a comfortable beginning weight and shape.
  • This chart makes a quick correction in the field rather cumbersome.
  • My system involves first making a normal zero angle computation. Then subtract the angle correction from the distance correction. If you computed a 36 inch drop at 500 yards and the hold down is 32 inches, remember this is a correction. for a high shot 32 inches higher than normal. Visualize the drop figure as a down vector. Use a mental thirty six inch ruler and pull the ruler up one yard stick above your aim point. Now, to correct for angle, slide the correction 32 inches up the yard stick. What did that do? It made the computed aim point (corrected for angle) 4 inches above the organ you selected for an aim point.
  • the method is to simply compute all we have discussed and then add this "holdunder.” This has proven safest and fastest in the field for me. Compute your hold point for zero elevation angle range. Put the pipper on him, divide it out and you know the distance. The cheese begins to get binding if he is at a high angle down or up from you.
  • the uphill/downhill corrected aim points is factored into the horizontally computed aim point, i.e., The 400 yard zero angle bullet drop is 18 inches from a 6 factor rifle.
  • the 400 yard zero angle bullet drop is 18 inches from a 6 factor rifle.
  • the Nosier reloading book gives the following data:
  • the computed lead for a moving animal is as follows:
  • This running animal shot is one we have to make occasionally and it is another factor in sighting in at 200 yards.
  • the 6 factor rifles are 1.7" high at 100 yards and that presents no overshoot problem. Hold dead on for your running shots.
  • the one 1.0 factor rifle that is a problem is "the 375 H&H Magnum which prints 3" high at 100 yards and 4" at 140 yards. This rifle caliber requires some thought about sight in distance. If you are shooting Grizzly Bear, sight in at 1" high at 100 yards and forget anything past 200 yards.
  • 440 yards is my personal limit for moving animal shots because the time of flight gets confused past that distance.
  • My .375 starts at 2600 fps, arrives at 400 yards at 1941 fps, for an average 2200 fps.
  • 440 yards is 1320 feet so I figure a tad over half a second to time on target.
  • the actual time of flight computed for 400 yards is is 0.5357. That's close enough for government work.
  • My Weatherby's average 2800 fps so their bullets get there in a tad under half a second.
  • the actual computed time of flight for 400 yards is 0.4447. This is not the most.precise art form so I am satisfied with this half second figure. At 200 yards, I don't even figure time on the fly.
  • Wind lag will be clockwise so it will be a plus. I am shooting a 10 factor .375 H&H magnum. For 400 yard drift computation, I add 10" to the 300 yard 10": 20 inch lag correction. Counter clockwise wind, lag factor will be a plus because the correction is in a clockwise direction. Plus 20" for the wind.
  • the pipper is calibrated at 6 MOA., 2. The chest is 30 " deep.
  • the distance is 500 yards
  • the pipper is 30 inches high at 500 yds, the bullet drops 36 inches, which is 6" down the post.
  • Illustration 13 400 yard elk reticle image.
  • the pipper is calibrated at 6 MOA.
  • the chest is 24 " deep.
  • the distance is 400 yards.
  • the pipper is 24 inches high at 400 yds, the bullet drops 24 inches, which is the top of the post
  • the pipper is 18 inches deep.
  • the bullet impact is 6 inches down the pipper, or 1/3 down the pipper.
  • the First step is Finding the Size of the Target. We need the height of the target before we can measure the distance to it. (The procedure is also found in any Boy Scout manual.) Canned numbers don't work Just as women come in different sizes, animal species do also For instance, a Powder River Break white- tail buck may be larger than a TuIe elk cow. Most sizes are listed in the Swarovski handout which accompanies the rifle scope.
  • the System uses Grid Lines (an inch angle ruler strung down the lower reticle wire) for measur- ing the distance to a target. This is a precision measuring system which is accurate within 6% of a laser device.
  • the Grid Lines are illustrated to the right with the Range Marker Bars (RMB) scribing the 2, 5, 7.5 and 10.5 "Inch Angle" marks. Determine the Grid Line by interpolation.
  • RMB Range Marker Bars
  • the Second Step Adjusts Bullet Drop.
  • the deer is 300 yards .30/06 (illustration rifle) zeros the #2 RMB at 300 yards - more on this in V Decal Section which follows. (You are provided a .30/06 Factor Decal to scope as a reminder.) Slide the 2nd bar to the point of his shoulder. With is your firing solution or sight picture.
  • TDS TRI-FACTOR Aiming System Learning to use the TDS TRI-FACTOR Aiming System might best be introduced by comparing it to the automobile Industrie's marketing of the automobile's automatic transmission.
  • the reticle has the appearance of a short christmas tree.
  • the System uses the crosshair as it was originally intended by the cartridge's inventor. We zero the crosshair at the appropriate range for that specific cartridge. This is 25 yards for a .22 rimfire rifle, 50 yards for the African bores and 100 yards for plains game rifles.
  • a .22 rimfire rifle (picture at right) zeros the crosshair at 25 yards, using a Straight Line Aiming Point In other words look at the point you want to hit (desired impact point) and then overlay the crosshair on it. Squeese the trigger. None take your eyes off the target.
  • the system uses a Straight Line Aim. Its intuitive. Like pointing your finger. The shot is instantaneous because it is intuitive or 25 Yard Sight Picture. "Brain Model" friendly.
  • This system instructs you to determine the distance to the center target (we will cover this in a few pages), focus on the target, slide the of a target at 25 yards. crosshair over it and fire.
  • the TDS TRI- FACTOR SYSTEM uses the crosshair for aiming during the Point Blank Range (PBR) phase of the cartridges whose Ps exceeds the 600 yard sight In.
  • PBR Point Blank Range
  • the Sierra Reloading book defines a 30/378 cartridge firing the .308 168 grain HPBT at 3,400 fps as having a 410 yard PBR; that is, when zeroed at 345 yards (the bullet's second crossing of the Optical Zero) the bullet will hit somewhere in a 10 inch circle should the shooter aim at the center of the circle from the muzzle to 410 yards (A to C in the PBR illustration above).
  • a 30/06 500 yard rifle (Tab One, Line 521) has an aiming error of less than an inch to 500 yards.
  • a "Bean Field" hunter will use the reticle to confirm the distances from 150 to 450 yards and use a sight picture aiming at the bottom of the deer's chest for that range. From 450 yards to 900 yards he will hold dead on. The Reticle's four drop down bars make this possible - and provide you a straight line aiming point to boot.
  • Figures 8 and 9 illustrate a national championship rifle shooter firing a series of shots while simultaneously undergoing thermal imagery brain studies of his techniques - good and bad
  • This elite shooter is wearing a rubber cap wired with numerous electrodes designed to interrogate the specific region of his body or brain that is involved in the psychopsysiological portion of the shot process.
  • the Reticle is calibrated to the bullet's specific Energy Maneuverability (EM).
  • Energy [en-ergy noun 1. The capacity for or predictability of vigorous activity;]
  • Maneuverability [ ma-neu-ver noun 1. A controlled change in movement or direction of a moving vehicle, as in the flight path of an aircraft . . . predictable path of a bullet.].
  • the single number is derived from the invented TDS TRI-FACTOR Mental Ballistics Method. It is faster and more accurate than a computer. It allows us to mentally predict an accurate speed and rate loss of energy. It is the reason the four RMBs provide accurate (1.5 inch) aiming guidance - so perfectly - with all 500 modern cartridges.
  • a 140 grain .308 Barnes X bullet begins life on the dealer's shelf along with all the other 140 grainers/ The manufacturer doesn't care what rifle you put them in.
  • One box of 140 grainers start life in a 30/378 at 3,700 f.p.s. The next may load in a .308 Winchester at 2,700 f.p.s.
  • each of the four Range Marker Bars (RMBs) is assigned.
  • the Tri-Factor patent application classifies all bullet flight in five phases - each of which expresses an idiosyncratic behavior peculiar to that phase and which requires special adjustment.
  • the Range Marker Bars are the only system in existence which provide this specialized service.
  • Each RMB has a specific Gyroscopic Stability Envelope (GSE) - with aiming corrections assigned for each "affect" that will cause a deflection from the TRI- FACTOR's designed 1.5 inch aiming cone of accuracy.
  • GSE Gyroscopic Stability Envelope
  • Each phase of bullet flight has individual problems unique to that GSE (call it a goose).
  • the crosshair is the first goose.
  • the 4 Range Marker Bars take the next 4 gooses. For instance, when the bullet is in its final, or transonic, phase of flight, it flies the 4th and 5th goose. Yaw of Repose (that's the critter) lives in the 4th and 5th goose. When a crosswind exceeds 10 m.p.h. - in the 4th and 5th goose only - It tilts the bullet by gyroscopic precession and the bullet climbs or descends l/4th the value of the horizontal precession.
  • Yaw of Repose (YR) is there in the other gooses but its effect is insignificant because of the speed and power of the bullet.
  • the TDS TRI-FACTOR System is one of the most researched shooting systems ever designed. It began when Ad Toepperwein (a world champion professional shooter from the early 20 th century who spent two of his final years teaching me trick shooting at his camp just north of my home in San Antonio, Texas. By the time I was 14, 1 could hit a thrown penny with a handgun. Years later, upon landing from a simulated combat mission, my Operations Officer told me I had to qualify with the handgun - "Gen. Le May's orders. Every fighter pilot in the Air Force has to shoot the thing.” I set the range record with a four-inch Model 29 .44 magnum. Unbeknownst to me, Gen. Le May was looking for a pistol team.
  • My combat training included some of the leading aces of the USAF, the German Heilwaffe, and the Japanese Air Self Defense Force.
  • the TDS TRI-FACTOR System is the result of an intense study which reflected on every bad shot I ever made and the resultant correction that eliminates them. It required the aiming system to mentally trigger psychophysiological responses that eliminate negative synapses.
  • the system guides the shooter into the proper mind set for each different type of shot by directing the brain to flow in the most effective path for executing differing conditions from a running snap shot to a hard held 900 yard precision shot. It had to be totally reliable in all conditions. It had to be a simple familiar visual pattern which provides accurate aiming guidance for all modem rifles - every thing from a .22 rimfire rifle to a 30/378.
  • the picture to the right illustrates the sight picture for correcting shot measured for the distance which Range Marker Bar #2 is responsible. This illustrates a no wind shot
  • This second picture (right) illustrates a 10 mile per hour right to left full value crosswind.
  • This third picture (right) illustrates a 20 per hour right to left full value crosswind - but in the RMB # 3 zone of responsibility.
  • the rule of thumb is to mentally construct a 45 degree vector at the appropriate angle and in a commensurate magnitude (use the length of the Wind Bar [10 mph] to interpolate the length of the adjustment) to adjust for the Yaw of Repose effect.
  • Shadowgraph photography has shown that the flowfield in the vicinity of a bullet most generally consists of laminar and turbulent regions.
  • the flowfield depends in particular on the velocity at which the bullet moves, the shape of the bullet and the roughness of its surface.
  • the flowfield changes tremendously, as the velocity drops below the speed of sound, which is about 1115 ft/s (340 m/s) at standard atmosphere conditions.
  • the TDS TRI-FACTOR MENTAL BALLISTICS PROGRAM chooses to eliminate consideration of the wildly divergent effects of transonic flight variable by termination of effect. What the Captain really means is that we terminate bullet correction at 1 ,500 fps except for the .22 caliber rim fire bullet, which is only predictable to 100 yards when fired at 1 , 100 fps muzzle velocity.
  • a piece of ordnance propelled through ambient air - such as a bullet or ballistic missile - moving through the atmosphere is affected by a variety of forces. Some of those forces are mass forces, which apply at the CG (center of gravity) of the body and depend on the body mass and the mass distribution. A second group offerees is called aerodynamic forces or what we unwashed call exterior ballistics. These forces result from the interaction of the flowfield with the bullet and depend on the shape and surface roughness of the body. Some aerodynamic forces depend on either yaw or spin or both. A summary of the most important forces affecting a bullet's motion through the atmosphere is shown in the table below (Nennstiel, Ruprecht).
  • Pitch Damping Y Y usually very small, important for stability
  • the centrifugal force and the Coriolis force are natural forces, which automatically arise from the fact that the earth is not resting, but rotates about its North-South axis.
  • the TDS TRI-FACTOR MENTAL BALLISTICS PROGRAM chose to ignore the affects of Coriolis force by (1) restricting reticle consideration of bullet flight to approximately .75 seconds and (2) negating the affect by making the final bullet zero at the 3 Range Marker Bar, which cancels it out.
  • the pressure differences at the bullet's surface result in a force, which is called the wind force.
  • the wind force seems to apply at the center of pressure of the wind force (CPW), which, for spin-stabilized bullets, is located in front of the CG.
  • the location of the CPW is not a constant and shifts as the fiowfi eld changes.
  • this couple is a free vector, which is called the aerodynamic moment of the windforce or, for short, the overturning moment.
  • the overturning moment tries to rotate the bullet around an axis, which passes through the CG and is perpendicular to the bullet's axis of form.
  • the wind force which applies at the center of pressure, can be substituted by a force ofthe same magnitude and direction plus a moment.
  • the force applies at the CG; the moment turns the bullet about an axis running through the CG.
  • the force which applies at the CG, into a force, which is antiparallel to the direction of movement of the CG, plus a force, which is perpendicular to this direction.
  • the first force is said to be the drag force or simply drag.
  • the other force is the lift force or lift for short.
  • lift suggests a low pressure zone formed by the upward curved wing surface of an airplane, but which is generally not true for a bullet.
  • the direction of the lift force depends on the orientation of the yaw angle.
  • a better word for lift force could be cross-wind force. This be what make the bullet go sideways in a crosswind.
  • Drag and lift apply at the CG and simply affect the motion of the CG. Of course, the drag retards this motion. The effects of the lift force will be met later.
  • the wind force is the dominant aerodynamic force.
  • Magnus force which turns out to be very important for bullet stability.
  • the gyroscopic effect also applies for the Magnus force.
  • the bullet's nose moves into the direction of the associated moment. (What the Captain really means: the bullet changes its angle of attack into the cross wind)
  • the Magnus force thus would have a stabilizing effect, as it tends to decrease the yaw angle, because the bullet's axis will be moved opposite to the direction of the yaw angle.
  • a similar examination shows that the Magnus force has a destabilizing effect and increases the yaw angle, if its center of pressure is located in front of the CG.
  • TDS TRI-FACTOR effective one-shot killing capability
  • the bullet's axis of symmetry generally points to the right and a little bit upward with respect to the direction of the velocity vector.
  • As an effect of this small inclination there is a continuous air stream, which tends to deflect the bullet to the right. We said deflect - not precess.
  • the occurrence of the yaw of repose is the morally sound reason for good Republican bullets to drift to the right (for right handed spin) or to the left for those mentally challenged left-handed spinners
  • YR causes the bullet to precess upward in a right wind; down in a left wind - enough to lift the bullet over the animal's his butt facing a right wind or creating a painful wound if he is facing a left wind which drives the bullet into his paunch.
  • Yaw of Repose The mean thing about Yaw of Repose is that it has no appreciable effect on a bullet in the first three gooses - the crosshair or first two bars. However, it will cause a gut shot or missed animal in the #3 and #4 bar's goose - if not accurately corrected. How? Correction is easier viewed than read.
  • the bullet has an aerodynamic laminar flow surrounding it so densely that the rifling brooves cannot extend through it. therefore the rifling cannot chop the wind.
  • the conditions were 745 measured yards to the town, a left-to-right perpendicular crosswind measured at 10 g 15 mph. Using the procedure discussed above, I killed 2 dogs with every 3 cartridges fired for a total of 15 dogs.
  • TDS TRI-FACTOR is the only system in existence that corrects these most complicated problems so easily.
  • the TDS TRI-FACTOR SYSTEM is composed equally of the Shooter, the Rifle and the Aiming System.
  • the Shooter portion is named TACTICAL STRESS MANAGEMENT. It resulted from the most humiliating thing I've ever had happen to me - which happened the day I met my very own personal monkey. I discovered that my "Monkey" lives on my back. He is there right now - ever vigilant to sense me moving out of my personal comfort zone. At the first whisper of anxiety, he charges onto my neck, shrieking, screaming and gouging my eyeballs with claws from Hell.
  • the TRI-FACTOR Tactical Stress Management System controls the monster. I designed it to defeat the Monkey - finally - and shoot the first 30 out of 30 in the match course. I needed it more in international competition.
  • My world record is held in pistol's two-day 60 shot marathon, the Ce ⁇ terfire Pistol competition. There were four world records on the line for the second day's final string of duelling; the defending Olympic Champion, the defending six-time U.S. Champion, the Russian and the Czech world records.
  • Figure 1 illustrates the proper sight picture for a buck running straight across from you at 12.5 mph.
  • Killing running game is an art - not a science.
  • the Lead Bar is for the shooter who doesn't practice running animal shots (who does?) and needs something that will work every time.
  • the RALP is designed to get as much science into the shot as pos sible (without all the confusion) by providing us with a simple intuitive and reliable aiming point that works effectively in the 0.5 to 1.5 seconds we have to make this type game shot.
  • the TDS TRI-FACTOR RALP is effective from 50 to 425 yards - the longest distance I have field tested it with a one-shot kill and had the harvest witnessed by an observer.
  • B (the crosshair) is the aiming point for a straight away shot.
  • A is the lead point for a 90 degree angle shot when the animal is trotting at 10 to 15 mph.
  • the Funnel is the Bar between A and B . We will explain it more thoroughly in the next pages.
  • the cognitive reaction to a buck breaking cover is "LOOK THE BULLET INTO THE TARGET'.
  • a point or two to remem ber A point or two to remem ber.
  • the hunter measures the distance to the buck by dividing the heighth of the buck's chest by the angle required to cover the chest.
  • line X is the distance from the shooter Theta to the buck.
  • the buck leaves Line X he will travel the length of Line "y" before the bullet gets there. That is why we have to lead the shot and can't point right at him.
  • the buck will travel about 25 inches while the bullet is travelling 100 yards. Should the buck double his speed we need to use 2 lead bars for him at 25mph. A hard run at 37.5 mph requires 3 lead bars.
  • the RALP is computed for the bullet to meet the buck on the Rifle line (hypotenuse) at line y. We shoot from theta.

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Aiming, Guidance, Guns With A Light Source, Armor, Camouflage, And Targets (AREA)

Abstract

L’invention concerne un réticule (16) pour viseur d’arme à feu, définissant un système d’indications dimensionnées espacées par des séparations déterminées dans le but d’améliorer la précision de la visée d’une arme à feu. Les indications peuvent comporter peuvent comporter des traits fins central vertical (19) et central horizontal (20) se coupant perpendiculairement, et quatre (ou un nombre supérieur ou inférieur) barres horizontales de marquage de distance (21, 22, 23, 24) disposées à des séparations angulaires déterminées sous le trait fin horizontal de façon à bissecter le trait fin central vertical. L’espacement des barres de marquage de distance sous le trait fin central horizontal est proportionnel à la déviation de la balle à des distances déterminées, selon les caractéristiques de la balle utilisée. Des longueurs relatives des barres de marquage de distance de chaque côté du trait fin central vertical sont proportionnelles à un vent latéral déterminé (par ex. 10 mph) à une distance d’une cible réfléchie par une barre de marquage de distance respective. Le procédé selon l’invention comprend les étapes consistant à utiliser le réticule pour déterminer la distance à la cible, et à utiliser la distance ainsi déterminée pour obtenir un point de visée précis sur le réticule. Ces inscriptions offrent également d’autres caractéristiques utiles permettant au tireur de calculer aisément mentalement les corrections à apporter dues au vent latéral, à des cibles en mouvement et au tir sur ces cibles situées au-dessus ou en dessous du tireur à un angle important.
PCT/US2004/040189 2004-12-01 2004-12-01 Reticule pour viseur d’arme a feu et son procede d’utilisation WO2006060007A1 (fr)

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EP1965166A1 (fr) * 2007-02-27 2008-09-03 Swarovski-Optik KG Dispositif pour la localisation des cibles
EP2802837A4 (fr) * 2012-01-10 2015-07-29 Dennis Sammut Appareil et procédé permettant de calculer des informations de point de visée
US9459077B2 (en) 2003-11-12 2016-10-04 Hvrt Corp. Apparatus and method for calculating aiming point information
US10180565B2 (en) 2017-02-06 2019-01-15 Sheltered Wings, Inc. Viewing optic with an integrated display system
US10254082B2 (en) 2013-01-11 2019-04-09 Hvrt Corp. Apparatus and method for calculating aiming point information
US10502529B2 (en) 2009-05-15 2019-12-10 Hvrt Corp. Apparatus and method for calculating aiming point information
USD871539S1 (en) 2018-01-18 2019-12-31 Nikon Inc. Reticle for a telescopic gun scope
US10534166B2 (en) 2016-09-22 2020-01-14 Lightforce Usa, Inc. Optical targeting information projection system
US10823532B2 (en) 2018-09-04 2020-11-03 Hvrt Corp. Reticles, methods of use and manufacture
US10907934B2 (en) 2017-10-11 2021-02-02 Sig Sauer, Inc. Ballistic aiming system with digital reticle
CN115079133A (zh) * 2022-06-14 2022-09-20 韩晓霞 一种基于激光测距技术的校准测距仪及其运行方法
US11454473B2 (en) 2020-01-17 2022-09-27 Sig Sauer, Inc. Telescopic sight having ballistic group storage
US11473873B2 (en) 2019-01-18 2022-10-18 Sheltered Wings, Inc. Viewing optic with round counter system
US11480781B2 (en) 2018-04-20 2022-10-25 Sheltered Wings, Inc. Viewing optic with direct active reticle targeting
US11675180B2 (en) 2018-01-12 2023-06-13 Sheltered Wings, Inc. Viewing optic with an integrated display system
US20230184513A1 (en) * 2011-01-01 2023-06-15 G. David Tubb Range compensating scope with ballistic effect compensating reticle, aim compensation method and adaptive method for compensating for variations in ammunition or variations in atmospheric conditions
US11966038B2 (en) 2018-03-20 2024-04-23 Sheltered Wings, Inc. Viewing optic with a base having a light module
US11994364B2 (en) 2018-08-08 2024-05-28 Sheltered Wings, Inc. Display system for a viewing optic

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US9459077B2 (en) 2003-11-12 2016-10-04 Hvrt Corp. Apparatus and method for calculating aiming point information
US9869530B2 (en) 2003-11-12 2018-01-16 Hvrt Corp. Apparatus and method for calculating aiming point information
US10731948B2 (en) 2003-11-12 2020-08-04 Hvrt Corp. Apparatus and method for calculating aiming point information
US10295307B2 (en) 2003-11-12 2019-05-21 Hvrt Corp. Apparatus and method for calculating aiming point information
EP1965166A1 (fr) * 2007-02-27 2008-09-03 Swarovski-Optik KG Dispositif pour la localisation des cibles
US10502529B2 (en) 2009-05-15 2019-12-10 Hvrt Corp. Apparatus and method for calculating aiming point information
US10948265B2 (en) 2009-05-15 2021-03-16 Hvrt Corp. Apparatus and method for calculating aiming point information
US11421961B2 (en) 2009-05-15 2022-08-23 Hvrt Corp. Apparatus and method for calculating aiming point information
US20230184513A1 (en) * 2011-01-01 2023-06-15 G. David Tubb Range compensating scope with ballistic effect compensating reticle, aim compensation method and adaptive method for compensating for variations in ammunition or variations in atmospheric conditions
US11965711B2 (en) 2012-01-10 2024-04-23 Hvrt Corp. Apparatus and method for calculating aiming point information
US10488153B2 (en) 2012-01-10 2019-11-26 Hvrt Corp. Apparatus and method for calculating aiming point information
US10488154B2 (en) 2012-01-10 2019-11-26 Hvrt Corp. Apparatus and method for calculating aiming point information
US11391542B2 (en) 2012-01-10 2022-07-19 Hvrt Corp. Apparatus and method for calculating aiming point information
US11181342B2 (en) 2012-01-10 2021-11-23 Hvrt Corp. Apparatus and method for calculating aiming point information
US10451385B2 (en) 2012-01-10 2019-10-22 Hvrt Corp. Apparatus and method for calculating aiming point information
EP2802837A4 (fr) * 2012-01-10 2015-07-29 Dennis Sammut Appareil et procédé permettant de calculer des informations de point de visée
US10895434B2 (en) 2013-01-11 2021-01-19 Hvrt Corp. Apparatus and method for calculating aiming point information
US11255640B2 (en) 2013-01-11 2022-02-22 Hvrt Corp. Apparatus and method for calculating aiming point information
US10254082B2 (en) 2013-01-11 2019-04-09 Hvrt Corp. Apparatus and method for calculating aiming point information
US11656060B2 (en) 2013-01-11 2023-05-23 Hvrt Corp. Apparatus and method for calculating aiming point information
US10458753B2 (en) 2013-01-11 2019-10-29 Hvrt Corp. Apparatus and method for calculating aiming point information
US10534166B2 (en) 2016-09-22 2020-01-14 Lightforce Usa, Inc. Optical targeting information projection system
US11619807B2 (en) 2017-02-06 2023-04-04 Sheltered Wings, Inc. Viewing optic with an integrated display system
US10180565B2 (en) 2017-02-06 2019-01-15 Sheltered Wings, Inc. Viewing optic with an integrated display system
US10732399B2 (en) 2017-02-06 2020-08-04 Sheltered Wings, Inc. Viewing optic with an integrated display system
US10520716B2 (en) 2017-02-06 2019-12-31 Sheltered Wings, Inc. Viewing optic with an integrated display system
US11187884B2 (en) 2017-02-06 2021-11-30 Sheltered Wings, Inc. Viewing optic with an integrated display system
US11940612B2 (en) 2017-02-06 2024-03-26 Sheltered Wings, Inc. Viewing optic with an integrated display system
US11927739B2 (en) 2017-02-06 2024-03-12 Sheltered Wings, Inc. Viewing optic with an integrated display system
US11921279B2 (en) 2017-02-06 2024-03-05 Sheltered Wings, Inc. Viewing optic with an integrated display system
US10606061B2 (en) 2017-02-06 2020-03-31 Sheltered Wings, Inc. Viewing optic with an integrated display system
US10866402B2 (en) 2017-02-06 2020-12-15 Sheltered Wings, Inc. Viewing optic with an integrated display system
US10852524B2 (en) 2017-02-06 2020-12-01 Sheltered Wings, Inc. Viewing optic with an integrated display system
US11725908B2 (en) 2017-10-11 2023-08-15 Sig Sauer, Inc. Digital reticle system
US11287218B2 (en) 2017-10-11 2022-03-29 Sig Sauer, Inc. Digital reticle aiming method
US10907934B2 (en) 2017-10-11 2021-02-02 Sig Sauer, Inc. Ballistic aiming system with digital reticle
US11675180B2 (en) 2018-01-12 2023-06-13 Sheltered Wings, Inc. Viewing optic with an integrated display system
USD871539S1 (en) 2018-01-18 2019-12-31 Nikon Inc. Reticle for a telescopic gun scope
US11966038B2 (en) 2018-03-20 2024-04-23 Sheltered Wings, Inc. Viewing optic with a base having a light module
US11480781B2 (en) 2018-04-20 2022-10-25 Sheltered Wings, Inc. Viewing optic with direct active reticle targeting
US11994364B2 (en) 2018-08-08 2024-05-28 Sheltered Wings, Inc. Display system for a viewing optic
US10895433B2 (en) 2018-09-04 2021-01-19 Hvrt Corp. Reticles, methods of use and manufacture
US11293720B2 (en) 2018-09-04 2022-04-05 Hvrt Corp. Reticles, methods of use and manufacture
US10823532B2 (en) 2018-09-04 2020-11-03 Hvrt Corp. Reticles, methods of use and manufacture
US11473873B2 (en) 2019-01-18 2022-10-18 Sheltered Wings, Inc. Viewing optic with round counter system
US11454473B2 (en) 2020-01-17 2022-09-27 Sig Sauer, Inc. Telescopic sight having ballistic group storage
CN115079133A (zh) * 2022-06-14 2022-09-20 韩晓霞 一种基于激光测距技术的校准测距仪及其运行方法

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