Range-finding and compensating scope with ballistic effect compensating reticle, aim compensation method and adaptive method for compensating for variations in ammunition or variations in atmospheric conditions
11480411 · 2022-10-25
Inventors
Cpc classification
F41G3/06
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F41G1/38
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
Abstract
A range-finding and ballistics effect compensating scope 804 with a ballistic effect compensating reticle aim point field 650 and ammunition adaptive aim compensation method for rifle sights or projectile weapon aiming systems includes (a) a primary aiming point 658 adapted to be sighted-in at a first selected range and (b) the locus of the RF beam for sensing range 29 to a selected target 28. The when firing, the reticle's aim point field also includes a sloped array of wind dots (e.g., 660) illustrating aim points for a range of crosswind conditions. The method for compensating for a projectile's ballistic behavior permits the shooter to sense or measure the LOS range to target 29 and sense or input the slope angle 27 and local or nominal air density ballistic characteristics (e.g., air density), and then display corrected hold points.
Claims
1. A range-finding and compensating scope assembly with a ballistic effect compensating reticle including a system to display aiming indicia for a rifle firing a first selected spin stabilized projectile under sensed or known local atmospheric and wind conditions, comprising: (a) a ballistics effect compensating reticle display field having a horizontal crosshair indicia array aligned on a horizontal crosshair axis and being disposed or projected along an optical path and viewable by a shooter and (b) a laser signal emitter communicating with a microprocessor in operative communication with a range finding signal detector; wherein said microprocessor is programmed to generate a microprocessor-generated sensed Line of Sight Range signal for communication to an optical display element located along the optical path, wherein said optical display element generates a targeting display image upon said reticle display field representing a sensed and corrected Effective Hold Point range to a target; wherein said ballistics effect compensating reticle display field is viewable through the range-finding and compensating scope assembly, and said ballistics effect compensating reticle display field includes a plurality of aiming points disposed thereupon, said plurality of aiming points including a first array of windage aiming marks spaced apart along a non-horizontal axis for wind-adjusted aim at a first predetermined range, wherein said first array of windage aiming marks define a first sloped row of windage aiming points; said first sloped row of windage aiming points being aligned along said non-horizontal axis which is positioned below and not parallel to said horizontal crosshair indicia array axis, wherein said first sloped row of windage aiming points has a slope which is a function of the direction and velocity of the first selected projectile's stabilizing spin and provides compensated aiming indicia for said first selected projectile's crosswind jump at said sensed and corrected Effective Hold Point range.
2. The range-finding and compensating scope assembly of claim 1, wherein said ballistics effect compensating reticle display field's first array of windage aiming marks correspond to a plurality of predetermined wind velocity conditions at a first predetermined Effective Hold Point range; wherein said reticle display field's first array of windage aiming marks at said predetermined wind velocity conditions and said first predetermined Effective Hold Point range correspond to a predetermined baseline atmospheric condition.
3. The range-finding and compensating scope assembly of claim 2, wherein said reticle display field's first array of windage aiming marks at said predetermined wind velocity conditions and said first predetermined Effective Hold Point range correspond to a predetermined baseline air density.
4. The range-finding and compensating scope assembly of claim 3, wherein said reticle display field includes a second array of windage aiming marks aligned along a second sloped axis which is substantially parallel to but above or below said first array of windage aiming marks, wherein said second array of windage aiming marks defines a second sloped row of windage aiming points at said predetermined wind velocity conditions and at said sensed and corrected Effective Hold Point range.
5. The range-finding and compensating scope assembly of claim 4, wherein said reticle display field further comprises additional arrays of windage aiming marks at said predetermined wind velocity conditions and at a plurality of predetermined Effective Hold Point ranges corresponding to additional selected points of aim for additional selected ranges.
6. The range-finding and compensating scope assembly of claim 1, wherein ballistic compensation information comprising at least one of (a) a sensed or measured Line of Sight Range, (b) a sensed or measured slope angle, (c) a sensed or measured crosswind speed, and (d) a sensed or measured atmospheric condition is either programmed into the microprocessor or defined in the alignment of the first array of windage aiming marks.
7. The range-finding and compensating scope assembly of claim 6, wherein the ballistic compensation information is encoded into the plurality of aiming points disposed upon said ballistics effect compensating reticle display field, wherein the encoding is done via display of an air density correction encoding scheme that comprises an array of range-specific density correction pointers being displayed on said ballistics effect compensating reticle display field at selected ranges.
8. The range-finding and compensating scope assembly of claim 6, wherein said first selected projectile is fired at a selected standard initial muzzle velocity, whereby said first selected projectile when fired at the selected standard initial muzzle velocity is assigned a nominal Density Altitude (“DA”) baseline or index value and wherein a second selected projectile from a different type of ammunition may be fired from said rifle at said assigned nominal DA baseline or index value for selected target surfaces out to a sensed and corrected Effective Hold Point range of 900 yards.
9. The range-finding and compensating scope assembly of claim 1, wherein said plurality of aiming points positioned for ballistic effects compensated aim at said sensed and corrected Effective Hold Point range comprising said first array of windage aiming marks spaced apart along said non-horizontal axis at lateral spacings corresponding to selected increments of lateral wind velocity.
10. The range-finding and compensating scope assembly of claim 9, wherein said plurality of aiming points positioned for ballistic effects compensated aim at said sensed and corrected Effective Hold Point range further comprise a second array of windage aiming marks which is spaced from said first array of windage aiming marks, said second array of windage aiming marks spaced apart along a second non-horizontal axis at said lateral spacings corresponding to said selected increments of lateral wind velocity of said first array of windage aiming marks.
11. A method for sensing a Line of Sight (“LOS”) range to a selected target surface when using a selected rifle firing a first selected ammunition and generating a reticle display for a shooter which provides environmental and ballistically corrected aim points for sensed or measured local atmospheric conditions including crosswind velocities, comprising: providing a range-finding and compensating scope assembly and system with a ballistic effect compensating reticle display field disposed or projected along an optical path within said range-finding and compensating scope assembly and system and viewable by the shooter, said system also including a range-finding signal emitter communicating with a microprocessor programmed to generate a signal communicated to an optical element establishing a projected targeting display image upon said ballistics effect compensating reticle display field representing a sensed and corrected Effective Hold Point (“EHP”) range corresponding to a sensed range to the selected target surface; wherein said ballistic effect compensating reticle display field is viewable through the scope assembly, and said ballistics effect compensating reticle display field includes a main aiming point in a horizontal crosshair indicia array axis and above a plurality of downrange aiming points positioned for ballistic effects compensated aim at the EHP range and a range of crosswind speeds and including at least a first array of windage aiming marks spaced apart along a first non-horizontal axis, wherein said first array of windage aiming marks define at least a sloped row of windage aiming points, wherein said first non-horizontal axis is not parallel to said horizontal crosshair indicia array axis; actuating a first Range Finder aiming display mode in which said range finding signal emitter is aimed at the selected target surface by aiming or aligning the ballistics effect compensating reticle display field main aiming point directly at or upon said selected target surface while the Line of Sight (LOS) range is sensed; calculating a sensed and corrected Display Effective Hold Point range from the LOS range and selected additional information including, optionally, slope angle, air density, and ammunition ballistics information; and in response to said calculation, actuating a second display mode for shooting wherein at least said sloped row of windage aiming points is displayed or highlighted, at least said sloped row of windage aiming points corresponding to said sensed and corrected Display Effective Hold Point range for engaging said selected target surface to provide the environmentally and ballistically corrected aim points for selected crosswind velocities at said sensed and corrected Display Effective Hold Point range.
12. The method for sensing the Line of Sight (“LOS”) range to the selected target surface when using the selected rifle firing the first selected ammunition and generating the reticle display of claim 11, wherein said step of calculating said sensed and corrected Display Effective Hold Point range includes: identifying, for a first selected projectile of the first selected ammunition, said first selected projectile's associated nominal Air Density ballistic characteristics and current environmental air density characteristics; determining, from said LOS range to the selected target surface, the nominal air density ballistic characteristics of the first selected projectile and the current environmental air density characteristics, a yardage equivalent aiming adjustment value “Delta Yard” for the selected rifle and said first selected projectile; and calculating said sensed and corrected Display Effective Hold Point range from the LOS range and the yardage equivalent aiming adjustment value “Delta Yard”.
13. The method for sensing the Line of Sight (“LOS”) range to the selected target surface when using the selected rifle firing the first selected ammunition and generating the reticle display of claim 12, wherein said step of calculating said sensed and corrected Display Effective Hold Point range includes: identifying the slope angle encountered while aiming at the selected target surface; determining, from said slope angle and said LOS range to the selected target surface, a cosine range aiming adjustment; and calculating said sensed and corrected Display Effective Hold Point range from the LOS range and the cosine range aiming adjustment.
14. The method for sensing the Line of Sight (“LOS”) range to the selected target surface when using the selected rifle firing the first selected ammunition and generating the reticle display of claim 11, further comprising: in response to the calculation of said sensed and corrected Display Effective Hold Point range, when actuating said second display mode for shooting, displaying a second array of windage aiming marks proximate said first array of windage aiming marks to provide upper and lower arrays of windage aiming marks which bracket the sensed and corrected Display Effective Hold Point range for said selected crosswind velocities.
15. The method for sensing the Line of Sight (“LOS”) range to the selected target surface when using the selected rifle firing the first selected ammunition and generating the reticle display of claim 14, further comprising: selecting, for said sensed or measured local atmospheric conditions, a windage hold point corresponding most closely to a closest or optimum windage aiming mark from said second array of windage aiming marks; and displaying a highlighted or illuminated windage aiming point corresponding to said optimum windage aiming mark at said sensed and corrected Display Effective Hold Point range in said reticle display.
16. The method for sensing the Line of Sight (“LOS”) range to the selected target surface when using the selected rifle firing the first selected ammunition and generating the reticle display of claim 11, further comprising: displaying a numerical value corresponding to said sensed and corrected Display Effective Hold Point range in said reticle display.
17. The method for sensing the Line of Sight (“LOS”) range to the selected target surface when using the selected rifle firing the first selected ammunition and generating the reticle display of claim 11, further comprising: selecting, for said sensed or measured local atmospheric conditions, a windage hold point corresponding most closely to a closest or optimum windage aiming mark from said first array of windage aiming marks spaced apart along said first non-horizontal axis defining said sloped row of windage aiming points; and displaying a highlighted or illuminated windage aiming point corresponding to said optimum windage aiming mark at said sensed and corrected Display Effective Hold Point range in said reticle display.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
(22) In order to provide context for the present invention, please refer again to Prior Art
(23) While an exemplary variable power LRF equipped scope 804 (see, e.g.,
(24) Turning next to
(25) Range-finding component subassembly 816 may be a near infrared laser projector consisting of a pulsed laser diode 834 in communication with the collimating lens 832, again mounted in an aligned or adjacent fashion relative to the objective lens 830 of the erect image telescope 804 to produce a small spot of light (e.g., at a range of 1000 yards or more). Range-finding component subassembly 816 is aligned or connected to scope body 814 and is shown in dashed lines in
(26) Returning to the exemplary embodiment of
(27) In the illustrated example, LRF scope system 811 includes circuitry connected and responsive to a laser or IR detector (not shown) located in proximity to the prism 828 and communicating with control circuit 840. The laser or IR detector (not shown) is preferably capable of being illuminated through the scope's objective lens 830, so both the laser projector and the laser or IR detector are “zeroed” in relationship to the DTR™ reticle 824. The laser generator 836 and control circuit 840, in operation, progress through a number of pulse timing iterations until a constant time delay value is obtained and which is indicative of a valid range measurement (in a known manner). Upon communicating this range measurement information to the microprocessor 838, an output thereof is communicated to a display driver 847 and which is in turn communicated to a light emitting display 848. Angled mirror 850 redirects the projected light or image from display 848, which is then passed through a display lens 852 and into prism 828 in response to an Effective Hold Point (“EHP”) range calculation undertaken in response to a program which controls microprocessor 838. In a preferred embodiment, the EHP range is displayed numerically in the reticle image for the user (e.g., “800 YDS” as seen in
(28) While variable power scopes typically include two focal planes, the reticle screen or glass (e.g. 16 or 824) used in connection with the reticles of the present invention (e.g., with aim point fields 150, 350 or 650) is preferably positioned at the first or front focal plane (“FP1”) between the distal objective lens (e.g. 12 or 830) and the erector lens (e.g. 18 (or 822 as seen in
(29) As noted above, the applicant's prior art DTAC™ reticles (e.g., as shown in
(30) Referring next to
(31) The system 810, reticle (e.g., with aim point fields 150, 350 or 650) and method of present invention as illustrated in
(32) The range finding and aim compensating system 810 and method of present invention as illustrated in
(33) The sloped downrange wind dots in aim point field 150 (e.g., for 800 yards, along sloped row 160A) have been configured or plotted to aid the shooter by illustrating the inter-relationship of the external ballistic effects observed and recorded by the applicant as part of the development work for the system and method of the present invention. In reticle aim point field 150, the windage aim point indicia or laterally offset wind dots on each sloped array of wind dots are not symmetrical about the vertical reference line 156, meaning that a full value windage offset indicator (e.g. 5 mph) on the left side of vertical crosshair 156 is not spaced from vertical crosshair 156 at the same distance as the corresponding full value windage offset indicator (e.g. 5 mph) on the right side of the vertical crosshair, for a given wind velocity offset.
(34) As noted above, the LRF scope reticles of the prior art (e.g., as illustrated in
(35) The applicant of the present invention re-examined these assumptions and empirically observed, recorded and plotted the actual ballistic performance for a series of carefully controlled shots at selected ranges, and the plotted observations have been used to develop improved reticle aim point field (e.g., 150) which has been demonstrated to be a more accurate predictor of the effects of atmospheric and environmental conditions on a bullet's flight.
(36) Experimental Approach and Prototype Development:
(37) As noted above the reticle systems (e.g., 200, 300 and 600) and the method of the present invention are useful to predict the performance of specific ammunition fired from a specific rifle system (e.g., 6), but can be used with a range of other ammunition by using pre-defined correction criteria. The data for the reticle aim point field 150 shown in
(38) The range finding and aim compensating system of the present invention (e.g., 804) preferably includes an aim point field (e.g., 150) with a vertical crosshair 156 and a horizontal crosshair 152 which intersect at a right angle and also includes a plurality of windage adjustment axes (e.g., 160A) arrayed beneath horizontal crosshair 152. The windage adjustment axes (e.g., 160A) are angled downwardly at a shallow angle (e.g., five degrees, for RH twist), meaning that they are not secondary horizontal crosshairs each being perpendicular to the vertical crosshair 156. Instead, each windage axis defines an angled or sloped array of windage offset adjustment indicia. If a windage axis line were drawn through all of the windage offset adjustment indicia corresponding to a selected range (e.g., 800 yards), that windage axis line would slope downwardly from horizontal at a small angle (e.g., five degrees), as illustrated in
(39) As noted above, the windage offset adjustment indicia on each windage adjustment axis are not symmetrical about the vertical crosshair 156 or symmetrical around the array of elevation indicia or nearly vertical central aiming dot line 154. The nearly vertical central aiming dot line 154 provides a “no wind zero” for selected ranges (e.g., 100 to more than 1500 yards, as seen in
(40) The phenomena or external ballistic effects observed by the applicant are not anticipated in the prior art for rifle scopes, but applicant's research into the scientific literature has provided some interesting insights. A scientific text entitled “Rifle Accuracy Facts” by H. R. Vaughn, and at pages 195-197, describes a correlation between gyroscopic stability and wind drift. An excerpt from another scientific text entitled “Modern Exterior Ballistics” by R. L. McCoy (with appended errata published after the author's death), at pages 267-272, describes a USAF scientific inquiry into what was called “Aerodynamic Jump” due to crosswind and experiments in aircraft. Applicant's experiments have been evaluated in light of this literature and, as a result, applicant has developed a model for two external ballistics mechanisms which appear to be at work. The first mechanism is now characterized, for purposes of the system and method of the present invention, as “Crosswind Jump” wherein the elevation-hold or adjustment direction (up or down) varies, depending on whether the shooter is compensating for left crosswind (270°) or right crosswind (90°), and the present invention's adaptation to these effects is illustrated in
(41) The second mechanism (dubbed “Dissimilar Wind Drift” for purposes of the system and method of the present invention) was observed as notably distinct lateral offsets for windage, depending on whether a crosswind was observed as left wind (270°) or right wind (90°). Referring again to
(42) Applicant's reticle system (e.g., 200, 300 or 600) permits the user or shooter to quickly align range finding and aim compensating system 810 toward a target of interest 28 (e.g., as shown in
(43) The range finding and aim compensating scope 804 and reticle of the present invention can be used with the popular M118LR 0.308 (or 7.62NATO) caliber ammunition which is typically provides a muzzle velocity of 2565 FPS. Turning now to
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(46) As noted above, the nearly but not exactly vertical central aiming dot line 354 is curved or skewed somewhat to the right of the true vertical reference line 356 to compensate for “spin drift” of a spin-stabilized bullet or projectile in its trajectory when there is no significant crosswind. The exemplary M24 or M40 variant rifle barrels (e.g., 7) have “right twist” inwardly projecting rifling which spirals to the right, or clockwise, from the proximal chamber to the distal muzzle of the barrel. The rifling (e.g., in barrel 7) engraves and imparts a corresponding clockwise stabilizing spin to the M118LR bullet (not shown). As the projectile or bullet travels an arcuate trajectory in its distal or down range ballistic flight between the muzzle and the target, the longitudinal axis of the bullet will deflect angularly to follow that arcuate trajectory. As noted above, the flying bullet's clockwise spin results in gyroscopic precession which generates a force that is transverse or normal (i.e., ninety degrees) to the arcuate trajectory, causing the bullet to deflect to the right. This effect is seen most clearly at relatively long ranges, where there is substantial arc to the trajectory of the bullet (e.g., as illustrated in
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(48) In
(49) The nearly vertical columns 362A, 362B, 364A, 364B, etc., spread as they extend downwardly to greater and greater ranges, but not symmetrically, due to the external ballistics factors including Crosswind Jump and Dissimilar Crosswind Drift, as discussed above. These nearly vertical columns define aligned angled columns or axes of aim points configured to provide an aiming aid permitting the shooter to compensate for windage, i.e. the lateral drift of a bullet due to any crosswind component. As noted above, downrange crosswinds will have an ever greater effect upon the path of a bullet with longer ranges. Accordingly, the vertical columns spread wider, laterally, at greater ranges or distances, with the two inner columns 362A and 364A being closest to the column of central aiming dots 354 and being spaced to provide correction for a five mile per hour crosswind component, the next two adjacent columns 362B, 364B providing correction for a ten mile per hour crosswind component, etc.
(50) In addition, a moving target must be provided with a “lead,” somewhat analogous to the lateral correction required for windage. The present scope reticle includes approximate lead indicators 366B (for slower walking speed, indicated by the “W”) and 366A (farther from the central aim point 358 for running targets, indicated by the “R”). These lead indicators 366A and 366B are approximate, with the exact lead depending upon the velocity component of the target normal to the bullet trajectory and the distance of the target from the shooter's position.
(51) As noted above, in order to use the elevation and windage aim point field 350 of
(52) It should be noted that each of the stadia markings 402 and 404 comprises a small triangular shape, rather than a circular dot or the like, as is conventional in scope reticle markings. The polygonal stadia markings of the present system place one linear side of the polygon (preferably a relatively flat triangle) normal to the axis of the stadia markings, e.g. the horizontal crosshair 352. This provides a precise, specific alignment line, i.e. the base of the triangular mark, for alignment with the right end or the bottom of the target or adjacent object, depending upon whether the length or the height of the object is being ranged. Conventional round circles or dots are subject to different procedures by different shooters, with some shooters aligning the base or end of the object with the center of the dot, as they would with the sighting field, and others aligning the edge of the object with one side of the dot. It will be apparent that this can lead to errors in subtended angle estimation, and therefore in estimating the distance to the target.
(53) Referring back to
(54) Range finding and aim compensating rifle scope 804 when equipped with aim compensating reticle 300 of
(55) DA represents “Density Altitude” and variations in ammunition velocity can be integrated into the aim point correction method (preprogrammed into memory accessible by microprocessor 838) by selecting a lower or higher DA correction number, and this part of the applicant's method referred to as “DA Adaptability”. This means that a family of reticles is readily made available for a number of different bullets for use with range finding and aim compensating scope 804. This particular example is for the USGI M118LR ammunition, which is a 0.308, 175 gr. Sierra™ Match King™ bullet, modeled for use with a rifle having scope 2.5 inches over bore centerline and a 100 yard zero. In computing the optimum EHP range, the bullet's flight path is defined to match the reticle at the following combinations of muzzle velocities and air densities:
(56) 2 k DA=2625 FPS and 43.8 MOA at 1100 yards
(57) 3 k DA=2600 FPS and 43.8 MOA at 1100 yards
(58) 4 k DA=2565 FPS and 43.6 MOA at 1100 yards
(59) 5 k DA=2550 FPS and 43.7 MOA at 1100 yards
(60) 6 k DA=2525 FPS and 43.7 MOA at 1100 yards
(61) where 1100 yard come-ups were used since this bullet is still above the transonic region. Thus, the reticle's density correction graphic indicia array 500 can be used with Density Altitude Graph 550 (or a corresponding Look Up Table programmed into scope 804) to provide the user with a convenient method to adjust or correct the selected aim point for a given firing solution when firing using different types of ammunition or in varying atmospheric conditions with varying air densities.
(62) In accordance with the method and system (e.g., 810) of the present invention, each user is preferably provided with information (e.g., a placard or card for each scope 804 which defines the bullet path values (come-ups) at selected (e.g., 100 yard) intervals. When the user sets up their rifle system (and programs scope 804), they chronograph their rifle and pick the Density Altitude which matches the system's (i.e., rifle+ammunition) velocity. Handloaders have the option of loading to that velocity to match the main reticle value. The conditions which result in a bullet path that matches the reticle is referred to throughout this as the “nominal” or “main” conditions. The scope legend (e.g., 326), viewed by zooming back to the minimum magnification, shows the model and revision number of the reticle from which can be determined the main conditions which match the reticle.
(63) Experienced long range marksmen and persons having skill in the art of external ballistics as applied to long range precision shooting will recognize that the present invention makes available a novel range finding and aim compensating system (e.g., 810) and ballistic effect compensating reticle system (e.g., 200, 300 or 600) for use in a projectile weapon aiming system adapted to provide a field expedient firing solution for a selected projectile, comprising: (a) a multiple point elevation and windage aim point field (e.g., 150, 350 or 650) including a primary aiming mark (e.g., 158, 358 or 658) indicating a primary aiming point adapted to be sighted-in at a first selected range (e.g., 200 yards); (b) the aim point field including a nearly vertical array of secondary aiming marks (e.g., 154, 354 or 654) spaced progressively increasing incremental distances below the primary aiming point and indicating corresponding secondary aiming points along a curving, nearly vertical axis intersecting the primary aiming mark, the secondary aiming points positioned to compensate for ballistic drop at preselected regular incremental ranges beyond the first selected range for the selected projectile having pre-defined ballistic characteristics where the aim point field, as displayed, also includes a sloped wind dot array or downrange array of windage aiming marks spaced apart along a secondary non-horizontal axes (e.g., 160A) intersecting a first selected secondary aiming point (e.g., corresponding to a selected EHP range). The first array of windage aiming marks includes a first windage aiming mark spaced apart to the left of the vertical axis at a first windage offset distance from the vertical axis selected to compensate for right-to-left crosswind of a preselected first incremental velocity (e.g., 5 mph) at the range of said first selected secondary aiming point, and a second windage aiming mark spaced apart to the right of the vertical axis at a second windage offset distance from the vertical axis selected to compensate for left-to-right crosswind of that same preselected first incremental velocity (e.g., 5 mph) at said range of said first selected secondary aiming point. The first array of windage aiming marks defining the highlighted or displayed sloped row of windage aiming points (e.g., as best seen in
(64) In the illustrated embodiments, the range finding and aim compensating scope 804 has a ballistic effect compensating reticle (e.g., 200, 300 or 600) with several sloped arrays of windage aiming marks which define sloped rows of windage aiming points having a negative slope which is a function of the right-hand spin direction for the projectile's stabilizing spin or a rifle barrel's right-hand twist rifling, thus compensating for the projectile's gyroscopic precession effects (including crosswind jump and dissimilar wind drift) and providing a more accurate compensated aim point for any range for which the projectile remains supersonic.
(65) The ballistic effect compensating reticle (e.g., 200, 300 or 600) has each secondary aiming point intersected by a secondary array of windage aiming marks (e.g., 360E, for 300 yds) defining the sloped row of windage aiming points having a slope which is a function of the direction and velocity of the projectile's stabilizing spin or a rifle barrel's rifling twist rate and direction, and that sloped row of windage aiming points are spaced laterally in increments selected to indicate crosswind speed intervals (e.g., 5 mph). In the range finding and aim compensating system 810 and the method of the present invention, aiming compensation for ballistics and windage for multiple preselected incremental crosswind velocities (e.g., 5, 10, 15, 20 and 25 mph) is sensed during a first LRF display mode, and then calculated and displayed during a second shooting display mode. In the illustrated embodiments, each sloped row of windage aiming points includes windage aiming marks positioned to compensate for leftward and rightward crosswinds of 10 miles per hour and 20 miles per hour at the range of the secondary aiming point corresponding to the sloped row of windage aiming points, and at least one of the sloped row of windage aiming points is bounded by laterally spaced distance indicators which, in the method of the present invention, are illuminated or designated in the reticle to show the shooter the closest row to that indicated from the LRF sensing step. So, for example, if the range to target 29 is for a range which corresponds to an EHP that falls between two sloped rows (e.g., if EHP is calculated to be between 800 yds and 850 yds, e.g., 825 yds, as shown in
(66) Using the DA adaptability numbers illustrated in
NAV−Current DA×ADC #=Delta Yard (Eq. 1)
And EHP is then calculated as:
EHP=LOS range−Delta Yard (Eq. 2)
So referring again to
(67) The method for calculating the adjusted optimum Effective Hold Point (“EHP”) for display in EHP display window 862 and for choosing which sloped row of wind dot lines to illuminate (when in shooting display mode) is illustrated in the process flow diagram of
(68) For reticles with aim point fields such as 150, 350 or 650, the reticle's permanently inscribed pattern of wind dots is always visible, and in scope 804 microprocessor 838 is programmed to Illuminate or designate the one sloped wind dot line array which most closely matches the stored EHP value. Optionally, as illustrated in diagram block 910, Optional if LOS range is under a first selected threshold range (e.g., 500 yds) and optimum EHP range is within a selected percentage (e.g. 10%) or a selected distance (e.g., 10 yards) of the one closest sloped row of wind dots illuminated, the controller can be programmed to illuminate ONLY the closest sloped row; however, if this condition is NOT true, then the scope 804 is programmed to surround or bracket the true aim point EHP by illuminating both the closest row of sloped wind dots AND the second closest sloped row. Alternatively, where the reticles (200, 300 or 600) exist only in software within scope 804, and are NOT permanently etched on a reticle surface 824, the microprocessor is programmed to display only one sloped row at exactly the EHP.
(69) Preferably, at least one of the sloped arrays windage aiming points is proximate an air density or projectile ballistic characteristic adjustment indicator such as the “Lazy” DA adjustment factors arrayed in density correction indicia array 670, and the air density or projectile ballistic characteristic adjustment indicator is preferably a Density Altitude (DA) correction indicator, but could also be expressed in air density units known with the acronym “DU.” Those density correction factors can also be used by the shooter “on the fly”, in case it is not possible to input current DA information to microprocessor 838.
(70) Generally, when using the range-finding and compensating scope 804 with a ballistic effect compensating reticle aimpoint field (e.g., 150, 350 or 650), if there is actually no crosswind, the nearly vertical array of secondary aiming marks (e.g., 154, 354 or 654) provide very clearly defined secondary aiming points along a curving, nearly vertical axis and are curved in a direction that is a function of the direction of the projectile's stabilizing spin from rifle the barrel (e.g., 7) rifling direction, thus compensating for spin drift at any sensed EHP range. The primary aiming mark (e.g., 358) formed by the intersection of the primary horizontal sight line (e.g., 352) and the nearly vertical array of secondary aiming marks provide a conspicuous indicator or “dot” which may be illuminated or highlighted during the LRF sensing step, while LRF-DTR scope 804 is operating in the LRF display mode, during which the shooter aims rifle system 810 so that the primary aiming mark (e.g., 158, 358 or 658) is aligned directly over or at the target surface. The main horizontal crosshair array (e.g., 152, 352 or 652) preferably includes a bold, widened portion (370L and 370R) located radially outward from the primary aiming point, the widened portion having an innermost pointed end located proximal of the primary aiming point which provides an aid when aiming the LRF for LOS range detection.
(71) The range-finding and ballistic effect compensating system 810 is shown with exemplary reticle aim point field (e.g., 150, 350 or 650) which preferably also includes at least a second array of windage aiming marks spaced apart along a second non-horizontal axis intersecting a second selected secondary aiming point; and the second array of windage aiming marks includes a third windage aiming mark spaced apart to the left of the vertical axis at a third windage offset distance from the vertical axis selected to compensate for right-to-left crosswind of the preselected first incremental velocity (e.g., 10 mph) at the range of said second selected secondary aiming point (e.g., 800 yards), and a fourth windage aiming mark spaced apart to the right of the vertical axis at a fourth windage offset distance from the vertical axis selected to compensate for left-to-right crosswind of the same preselected first incremental velocity at the same range, and the second array of windage aiming marks define another sloped row of windage aiming points having a slope which is also 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 the projectile's crosswind jump. In addition, the ballistic effect compensating reticle's aim point field also includes a third array of windage aiming marks spaced apart along a third non-horizontal axis intersecting a third selected secondary aiming point, where the third array of windage aiming marks includes a fifth windage aiming mark spaced apart to the left of the vertical axis at a fifth windage offset distance from the vertical axis selected to compensate for right-to-left crosswind of the preselected first incremental velocity at the range of said third selected secondary aiming point, and a sixth windage aiming mark spaced apart to the right of the vertical axis at a sixth windage offset distance from the vertical axis selected to compensate for left-to-right crosswind of said preselected first incremental velocity at said range of said third selected secondary aiming point; herein said second array of windage aiming marks define another sloped row of windage aiming points having a slope which is also 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 crosswind jump.
(72) The range-finding and ballistic effect compensating system 810 reticle (e.g., 200, 300 or 600) may also have the aim point field's first array of windage aiming marks spaced apart along the second non-horizontal axis to include a third windage aiming mark spaced apart to the left of the vertical axis at a third windage offset distance from the first windage aiming mark selected to compensate for right-to-left crosswind of twice the preselected first incremental velocity at the range of said second selected secondary aiming point, and have a fourth windage aiming mark spaced apart to the right of the vertical axis at a fourth windage offset distance from the second windage aiming mark selected to compensate for left-to-right crosswind of twice said preselected first incremental velocity at said range of said selected secondary aiming point. Thus the third windage offset distance is greater than or lesser than the fourth windage offset distance, where the windage offset distances are a function of or are determined by the direction and velocity of the projectile's stabilizing spin or a rifle barrel's rifling twist rate and direction, thus compensating for the projectile's Dissimilar Wind Drift. The ballistic effect compensating reticle has the third windage offset distance configured to be greater than the fourth windage offset distance, and the windage offset distances are a function of or are determined by the projectile's right hand stabilizing spin or a rifle barrel's rifling right-twist direction, thus compensating for said projectile's Dissimilar Wind Drift.
(73) Broadly speaking, the range finding and aim compensating system's reticle (e.g., 200, 300 or 600) has an aim point field configured to compensate for the selected projectile's ballistic behavior while developing a field expedient firing solution expressed two-dimensional terms of:
(74) (a) EHP range or distance, used to orient a field expedient aim point vertically among the secondary aiming marks in said vertical array, and
(75) (b) crosswind relative velocity, used to orient the aim point laterally among a selected array of windage hold points.
(76) The range-finding and ballistic effect compensating method for use when firing a selected projectile from a selected rifle or projectile weapon (e.g., 6 or 810) and developing a field expedient firing solution, comprises: (a) providing a range-finding and ballistic effect compensating system 810 with a ballistic effect compensating reticle system (e.g., 200, 300 or 600) comprising a multiple point elevation and windage aim point field (e.g., 150, 350 or 650) including a primary aiming mark (e.g., 158, 358 or 658) intersecting a nearly vertical array of secondary aiming marks spaced along a curving, nearly vertical axis, where the secondary aiming points are positioned to compensate for ballistic drop at preselected regular incremental ranges (e.g., every 25 yards or every 50 yards) beyond the first selected range for the selected projectile having pre-defined ballistic characteristics; and where the aim point field also includes a sloped row of wind dots or array of windage aiming marks spaced apart along a secondary non-horizontal axis intersecting that first selected secondary aiming point; wherein the sloped row of wind dots 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) sensing a LOS range to a target, based on the range to the target and the nominal air density ballistic characteristics of the selected projectile, determining a yardage equivalent aiming adjustment (or EHP) for the projectile weapon 810; (d) illuminating or displaying at least one sloped row of wind dots arrayed at a range corresponding to the sensed EHP and then evaluating the actual wind between the shooter and the target to then determine a windage hold point along that illuminated sloped row (based on any crosswind sensed or perceived), and then aiming the rifle or projectile weapon 810 using the yardage equivalent EHP aiming adjustment for elevation hold-off and holding laterally for the selected windage hold point.
(77) The range-finding and ballistic effect aim compensation method of the present invention includes providing ballistic compensation information as a function of and indexed according to an atmospheric condition such as density altitude (“DA”) for presentation to the shooter or user, and then associating that ballistic compensation information with the firearm scope reticle feature (e.g., the “lazy 7” at 800 yds from indicia array 670 in
(78) The range-finding and ballistic effect compensating system 810 is readily configured to adjust the point of aim of a projectile firing weapon or instrument firing a selected projectile under varying atmospheric and wind conditions (e.g. with a reticle such as 200, 300 or 600) and preferably includes a plurality of aiming points disposed upon that reticle, where a plurality of aiming points positioned for proper aim at various predetermined range-distances and wind conditions include at least a first array of windage aiming marks spaced apart along a non-horizontal axis (e.g., array 360-0 for 800 yards) to define the sloped row of windage aiming points having a slope which is a function of the direction and velocity of the selected projectile's stabilizing spin or a rifle barrel's rifling twist rate and direction, thus compensating for said selected projectile's crosswind jump; and where all of said predetermined range-distances and wind conditions are based upon a baseline atmospheric condition such as an expected air density. The range-finding and ballistic effect compensating system 810 optionally includes a means for determining existing density altitude characteristics (such as DA graph 550 in
(79) Preferably, the range-finding and ballistic effect compensating system's information is pre-programmed into the scope's memory, but may also be input via data interface 843 in a manner which mirrors or is consistent with the data encoded into the plurality of aiming points disposed upon the reticle (e.g. 200, 300 or 600), as best seen in
(80) As noted above, the applicant's initial work was directed to determining an aim point for one specific type of ammunition, and the invention now includes a range-finding and ballistic effect compensating system 810 for using an adaptive method allowing a shooter in the field to adapt to changes in available ammunition and compensate for variations in ammunition or atmospheric conditions. Illustrative examples are provided in
(81) So, for example, if a shooter's rifle (e.g., 6 or 810) is set up to shoot M118LR ammunition (i.e., with the 0.308 dia. 175 gr Sierra™ Match King™ HPBT projectile) at an initial muzzle velocity of 2565 Ft./Sec., the rifle may be assigned a nominal DA baseline or index value of 4 KDA (e.g., as shown and described in
(82) The ammunition-change adaptive range-finding and ballistic effect aim compensation method for use when firing first and second selected projectiles from a selected rifle or projectile weapon (e.g., 4 or 810) and developing a displayed field expedient firing solution (as a selected sloped row of windage dots) thus comprises: (a) providing a range-finding and ballistic effect compensating system 810 with a ballistic effect compensating reticle system (e.g., 200, 300 or 600) comprising a multiple point elevation and windage aim point field (e.g., 150, 350 or 650) including a primary aiming mark (e.g., 158, 358 or 658) intersecting a nearly vertical array of secondary aiming marks spaced along a curving, nearly vertical axis, the secondary aiming points positioned to compensate for ballistic drop at preselected regular incremental ranges beyond the first selected range for the selected projectile having 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 point; 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 first or second projectile's stabilizing spin or the rifle barrel's rifling twist rate and direction, thus compensating for said first or second projectile's crosswind jump; (b) based on at least the first selected projectile (e.g., M118LR ammunition (i.e., with the 0.308 dia. 175 gr Sierra™ Matchking™ HPBT projectile at an initial muzzle velocity of 2565 Ft./Sec.), identifying said first or projectile's associated nominal Air Density ballistic characteristics (e.g., 4 kDA); (c) sensing a LOS range to a target, based on the range to the target and the nominal air density ballistic characteristics of the first or second selected projectile, determining a yardage equivalent aiming adjustment or EHP for the projectile weapon and displaying, illuminating of highlighting one or two sloped wind dot lines corresponding to or bracketing the EHP range (d) determining a windage hold point, based on any crosswind sensed or perceived, and (e) aiming the rifle or projectile weapon using the displayed EHP yardage equivalent derived sloped row of windage aiming dots (e.g., for 800 yds when EHP is 800 yds) for elevation hold-off and choosing one or more of the wind dots in the sloped wind dot array to estimate the optimum windage hold point.
(83) Having described preferred embodiments of a new and improved reticle and method, it is believed that other modifications, variations and changes will be suggested to those skilled in the art in view of the teachings set forth herein. It is therefore to be understood that all such variations, modifications and changes are believed to fall within the scope of the present invention as set forth in the following claims.