Tactical ranging reticle for a projectile weapon aiming device
A reticle of a projectile weapon aiming system such as a riflescope includes a primary aiming mark adapted to be sighted-in at a first selected range and further includes a plurality of secondary aiming marks spaced apart below the primary aiming mark. The secondary aiming marks are positioned to compensate for ballistic drop at preselected incremental ranges beyond the first selected range, for a selected group of ammunition having similar ballistic characteristics. Angles subtended by adjacent aiming marks of the reticle can be adjusted by changing the optical power of the riflescope, to thereby compensate for ballistic characteristics of different ammunition. In some embodiments, the reticle includes a set of windage aiming marks spaced apart along at least one secondary horizontal axis intersecting a selected one of the secondary aiming marks, to facilitate compensation for the effect of crosswinds on the trajectory of the projectile.
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This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No. 60/626,967, filed Nov. 10, 2004.
COPYRIGHT NOTICE©2004 Leupold & Stevens, Inc. A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. 37 CFR § 1.71(d).
TECHNICAL FIELDThis application relates to projectile weapon aiming systems such as riflescopes, to reticle configurations for projectile weapon aiming systems, and to associated methods of compensating for ballistic characteristics.
BACKGROUND OF THE INVENTIONProjectile weapon aiming systems are discussed herein principally with reference to their use on rifles and embodied in telescopic sights commonly known as riflescopes. It will become apparent, however, that projectile weapon aiming systems may include aiming devices other than riflescopes, and may be used on weapons other than rifles, which are capable of propelling projectiles along substantially predeterminable trajectories, e.g., handguns, crossbows, and artillery.
A factor that must be taken into account in long-range shooting is the curved trajectory traversed by a bullet or other projectile as it falls from its initial trajectory while traveling the distance from the gun to the target, i.e., “range.” An aiming line of sight emanating from a reticle aiming mark of a riflescope rigidly affixed to the gun is straight, and hence the line of sight can intersect the curved trajectory only at a discrete range. At other ranges the projectile will pass below the aiming line of sight, necessitating the use of elevation adjustments for aiming.
A challenge in a long-range shooting environment is ranging a fairly small target at long distances. Typically, an operator looks for a target of a known height. For example, a operator may search for a target of approximately one meter in height or length, or other known target sizes that can be easily superimposed or divided to provide a one meter target. The target is then bracketed between reticle aiming marks which represent angularity. The known target height is divided by the bracketed angular value which may be measured in milliradians to provide a range. A ranging reticle may have a 10 milliradian scale to range a one meter target within an average effective range of 100 meters to 1000 meters. The scale is non-linear and the ranging process is easily implemented to 500 meters. In practice, a one meter target will subtend 10 milliradians at 100 meters, and two milliradians at 500 meters. At 1000 meters, the target will subtend one milliradian and the operator must perform 50% of the effective range estimation within the span of 1 milliradian. This becomes a difficult task due to the lack of scale resolution and because the target is further away.
A “mil-dot” reticle was developed by the U.S. Marine Corps in the late 1970s as an aid for a soldier in estimating distances. The mil-dot reticle has since become the military standard for range estimating within all branches of the service. The term “mil-dot” refers to milliradian, and the dot is spaced in 1 mil increments on the crosshairs. By using a formula, a table is generated based on the sized of the target being range-estimated. The viewed target is bracketed between the dots and the generated table is consulted. The round or football-shaped dots of a mil-dot reticle often obstruct viewing in long ranges. Furthermore, as with other conventional reticles, the mil-dot reticle does not provide sufficient scale resolution for ranges exceeding 500 meters.
U.S. Pat. No. 6,032,374 of Sammut and U.S. Pat. No. 5,920,995 of Smith, propose reticles having a series of secondary aiming marks spaced below a primary aiming mark at predetermined intervals for compensating for bullet drop. Sammut and Smith further include a rangefinder offset from the crosshairs for determining or estimating an observed range based on an object's height. The rangefinder has evenly spaced marks at a scale to assist in long distance estimation. After determining a range, the shooter selects the secondary aiming mark most closely corresponding to the observed range. However, the rangefinders are separate from the crosshairs and cannot be used for ballistic drop compensation or for horizontal leading. The secondary aiming marks of Sammut and Smith are not scaled to assist in accurately estimating ballistic drop and horizontal leading for distances greater than 500 meters.
The present inventors have recognized a need for an improved projectile weapon aiming system for accurately compensating for ballistic drop and windage for a variety of ammunition having different ballistic characteristics.
SUMMARY OF THE INVENTIONIn accordance with preferred embodiments, a reticle is located proximate a rear focal plane of a riflescope, an erector lens assembly and an ocular of the riflescope. The reticle is for use in a projectile weapon aiming system and includes a primary aiming mark and primary horizontal and vertical sight lines. The primary horizontal and vertical sight lines include a central portion extending radially from a primary aiming mark and a post portion extending radially from the central portion. The post portions may be at least three times thicker than the central portions to draw a shooter's eye to the thinner central portions.
Secondary and tertiary marks are positioned on the sight lines to provide range finding and lead compensation for distances less than 500 meters. Tertiary marks may be disposed equidistantly between adjacent secondary marks to subdivide a unit of measure indicated by the secondary marks. Quaternary or long range marks are positioned on the sight lines and provide scale resolution for range finding and lead compensation at distances greater than 500 meters. The quaternary marks are positioned proximate to the post portions and remote from the primary aiming mark to reduce visual obstruction for short range targets. A plurality of quaternary marks may be disposed between a pair of secondary marks to indicate incremental units of measure. The secondary, tertiary, and quaternary aiming marks are further positioned to provide hold over compensation for ballistic drop at preselected incremental ranges for an elected group of cartridges. The secondary, tertiary, and quaternary aiming marks may have a thickness approximately equal to the central portions to reduce visual obstruction.
Additional aspects and advantages of this invention will be apparent from the following detailed description of embodiments, which proceeds with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Throughout the specification, reference to “one embodiment,” “an embodiment,” or “some embodiments” means that a particular described feature, structure, or characteristic is included in at least one embodiment. Thus appearances of the phrases “in one embodiment,” “in an embodiment,” or “in some embodiments” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
Furthermore, the described features, structures, characteristics, and methods may be combined in any suitable manner in one or more embodiments. Those skilled in the art will recognize that the various embodiments can be practiced without one or more of the specific details or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or not described in detail to avoid obscuring aspects of the embodiments.
Reticle 40 is located in the optical path between objective 22 and ocular 26 and more preferably between erector lens assembly 30 and ocular 26, at or adjacent second focal plane 32. By way of example, reticle 40 may be used in a riflescope 10 in a configuration of certain riflescopes sold by Leupold & Stevens, Inc., Beaverton, Oregon, USA under the trademarks LPS®, VARI-X®, VX®, and others. However, the reticles described herein are not limited to use in riflescopes or with rifles, but may also be used in various other types of sighting devices and projectile weapon aiming devices and may be used to aim one or more of a variety of projectile weapons, such as rifles, pistols, crossbows, artillery, and others.
The primary horizontal and vertical sight lines 52, 54 include central portions 56, 58 respectively that extend radially from primary aiming point 50. Primary horizontal and vertical sight lines 52, 54 further include one or more widened post portions 60, 62, respectively, that extend radially from a corresponding central portion 56, 58. Post portions 60, 62 may be one and a half times thicker than central portions 56, 58 of primary horizontal and vertical sight lines 52 and 54, and may be at least three times thicker, to draw a shooter's eye to the thinner central portions 56, 58 and thereby help the shooter to locate primary aiming 50. In some embodiments, innermost ends 64 of widened post portions 60, 62 may serve as reference points for range estimation or windage compensation.
Referring to
The reticle 40 may further include horizontal and vertical tertiary aiming marks 70a-d, 72a-d disposed on corresponding central portions 56, 58. The tertiary marks 70a-d, 72a-d subdivide the measure between the secondary aiming marks 66a-e, 68a-e into equal halves. Accordingly, a single tertiary aiming mark 70a-d, 72a-d is disposed equidistant between two adjacent secondary aiming marks 66a-e, 68a-e. In the depicted embodiment, a tertiary aiming mark 70a-d, 72a-d measures 0.5 milliradians from an adjacent secondary aiming mark 66a-e, 68a-e. As with the secondary aiming marks 66a-e, 68a-e, the tertiary aiming marks 70a-d, 72a-d have a thickness that is approximately equal to or less than the respective central portions 56, 58. The tertiary aiming marks 70a-d, 72a-d may have a length less than the secondary aiming marks 66a-e, 68a-e to indicate the measure of a lesser unit value.
The reticle may further include horizontal and vertical quaternary aiming marks 74a-d, 76a-d disposed on corresponding central portions 56, 58. The quaternary aiming marks 74a-d, 76a-d further subdivide the measure between adjacent secondary aiming marks 66a-e, 68a-e. The quaternary aiming marks may also be 74a-d, 76a-d referred to as long range aiming marks as they provide a scale for distances at greater than 500 meters. The quaternary aiming marks 74a-d, 76a-d indicate less unit value than the tertiary aiming marks 70a-d, 72a-d. Thus, a plurality of quaternary aiming marks 74a-d, 76a-d may be incrementally disposed between secondary aiming marks 66a-e, 68a-e. The quaternary aiming marks 74a-d, 76a-d may indicate 0.2, 0.25, and 0.33 value of a measure between a pair of adjacent secondary aiming marks 66a-e, 68a-e. With secondary aiming marks 66a-e, 68a-e spaced one milliradian apart, the quaternary aiming marks 74a-d, 76a-d may indicate 0.2, 0.25, or 0.33 milliradians. The quaternary aiming marks 74a-d, 76a-d have a thickness that is approximately equal to or less than the respective central portions 56, 58. The quaternary aiming marks 74a-d, 76a-d may have a length less than the secondary aiming marks 66a-e, 68a-e and the tertiary aiming marks 70a-d, 72a-d to indicate the measure of a lesser unit value. Although milliradians have been referenced herein, alternative units may be used to reference an angle subtend, such as minute of angle (MOA) wherein 1 MOA= 1/60th degree.
The secondary and tertiary aiming marks 66a-e, 68a-e, 70a-d, 72a-d provide ranging and leading reference for distances up to 500 meters. For distances greater than 500 meters, the quaternary aiming marks 74a-d, 76a-d provide scale resolution for increased ranging and leading precision. The finer increments of the vertical quaternary aiming marks 76a-d enhance the ability to use the reticle for projectile drop compensation at greater distances. The finer increments of the horizontal quaternary aiming marks 74a-d can be used at greater distances to accurately estimate windage deflection trajectory and to effectively lead moving targets. The finer thickness of marks 66a-e, 68a-e, 70a-d, 72a-d, 74a-d, 76a-d reduces visual obstruction of a target and facilitates ranging and leading techniques. The thickness of the marks 66a-e, 68a-e, 70a-d, 72a-d, 74a-d, 76a-d is sized appropriately to the magnification for which the reticle is designed. In operation, the scale provided by the reticle 40 may be subdivided and/or combined by a trained operator to produce reference combinations for target ranging, leading, and holdover precision.
The primary aiming point 50 may be embodied as a transparent aperture with the central portions 56, 58 terminating prior to their intersection. So embodied, the primary aiming point 50 reduces obstruction for improved target acquisition at long ranges.
In the depicted embodiment of
Quaternary aiming marks 74a-d, 76a-d are preferably disposed remote from the primary aiming point 50 and proximate to the widened post portions 60, 62. The distance proximate to the post portions 60, 62 is referred to herein as the corner areas 78. In
In
As can be appreciated,
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Projectile weapon aiming systems have been described herein principally with reference to their use with rifles and embodied as riflescopes. However, skilled persons will understand that projectile weapon aiming systems may include aiming devices other than riflescopes, and may be used on weapons other than rifles, which are capable of propelling projectiles along substantially predeterminable trajectories, e.g., handguns, crossbows, and artillery. Thus, it will be obvious to those having skill in the art that many changes may be made to the details of the above-described embodiments without departing from the underlying principles of the invention. The scope of the present invention should, therefore, be determined only by the following claims.
Claims
1. A reticle for a projectile weapon aiming system, comprising:
- a primary horizontal sight line including, a horizontal central portion, and a horizontal post portion being at least one and a half times thicker than the horizontal central portion;
- a primary vertical sight line including, a vertical central portion, and a vertical post portion being at least one and a half times thicker than the vertical central portion, and
- wherein the primary horizontal and vertical sight lines define and extend radially from a primary aiming point;
- a plurality of vertical secondary aiming marks each indicating an equal unit of measure and intersecting the vertical central portion; and
- a plurality of vertical long range aiming marks each indicating an equal unit of measure, intersecting the vertical central portion, and disposed between a pair of vertical secondary aiming marks in closest proximity to the vertical post portion,
- wherein an area between the vertical secondary aiming mark closest to the primary aiming point and the primary aiming point is devoid of vertical long range aiming marks.
2. The reticle of claim 1, further comprising:
- a plurality of horizontal secondary aiming marks each indicating an equal unit of measure and intersecting the horizontal central portion; and
- a plurality of horizontal long range aiming marks each indicating an equal unit of measure, intersecting the horizontal central portion, and disposed between a pair of horizontal secondary aiming marks in closest proximity to the horizontal post portion,
- wherein an area between the horizontal secondary aiming mark closest to the primary aiming point and the primary aiming point is devoid of horizontal long range aiming marks.
3. The reticle of claim 2, further comprising:
- a plurality of horizontal tertiary aiming marks intersecting the horizontal central portion, each horizontal tertiary aiming mark disposed between and equidistant to a pair of horizontal secondary aiming marks; and
- a plurality of vertical tertiary aiming marks intersecting the vertical central portion, each vertical tertiary aiming mark disposed between and equidistant to a pair of vertical secondary aiming marks.
4. The reticle of claim 3, wherein each horizontal and vertical tertiary aiming mark indicates 0.5 milliradians from adjacent secondary aiming marks.
5. The reticle of claim 3, wherein the thickness of the horizontal and vertical tertiary aiming marks is approximately equal to the thickness of the primary horizontal and vertical sight lines.
6. The reticle of claim 2, wherein each horizontal and vertical secondary aiming mark indicates 1 milliradian from an adjacent secondary aiming mark.
7. The reticle of claim 2, wherein the thickness of the horizontal and vertical secondary aiming marks is approximately equal to the thickness of the primary horizontal and vertical sight lines.
8. The reticle of claim 2, wherein each horizontal and vertical long range aiming mark indicates less than 0.5 milliradians from an adjacent long range aiming mark.
9. The reticle of claim 8, wherein each horizontal and vertical long range aiming mark indicates 0.2 milliradians from an adjacent long range aiming mark.
10. The reticle of claim 2, wherein the thickness of the horizontal and vertical long range aiming marks is approximately equal to the thickness of the primary horizontal and vertical sight lines.
11. The reticle of claim 1, wherein the primary aiming point is transparent.
12. A riflescope comprising:
- an elongate housing supporting an objective lens and an eyepiece lens proximate opposite ends of the housing, and further supporting an erector lens assembly between the objective lens and the eyepiece lens;
- a reticle positioned between the erector lens assembly and the eyepiece, the reticle including, a primary horizontal sight line including, a horizontal central portion, and a horizontal post portion being at least one and a half times thicker than the horizontal central portion; a primary vertical sight line including, a vertical central portion, and a vertical post portion being at least one and a half times thicker than the vertical central portion, and wherein the primary horizontal and vertical sight lines define and extend radially from a primary aiming point, a plurality of vertical secondary aiming marks each indicating an equal unit of measure and intersecting the vertical central portion, and a plurality of vertical long range aiming marks each indicating an equal unit of measure, intersecting the vertical central portion, and disposed between a pair of vertical secondary aiming marks in closest proximity to the vertical post portion, wherein an area between the vertical secondary aiming mark closest to the primary aiming point and the primary aiming point is devoid of vertical long range aiming marks.
13. The riflescope of claim 12, wherein the reticle further comprises:
- a plurality of horizontal secondary aiming marks each indicating an equal unit of measure and intersecting the horizontal central portion; and
- a plurality of horizontal long range aiming marks each indicating an equal unit of measure, intersecting the horizontal central portion, and disposed between a pair of horizontal secondary aiming marks in closest proximity to the horizontal post portion,
- wherein an area between the horizontal secondary aiming mark closest to the primary aiming point and the primary aiming point is devoid of horizontal long range aiming marks,
14. The riflescope of claim 13, wherein the reticle further comprises:
- a plurality of horizontal tertiary aiming marks intersecting the horizontal central portion, each horizontal tertiary aiming mark disposed between and equidistant to a pair of horizontal secondary aiming marks; and
- a plurality of vertical tertiary aiming marks intersecting the vertical central portion, each vertical tertiary aiming mark disposed between and equidistant to a pair of vertical secondary aiming marks.
15. The riflescope of claim 13, wherein each horizontal and vertical tertiary aiming mark indicates 0.5 milliradians from adjacent secondary aiming marks.
16. The riflescope of claim 13, wherein the thickness of the horizontal and vertical tertiary aiming marks is approximately equal to the thickness of the primary horizontal and vertical sight lines.
17. The riflescope of claim 13, wherein each horizontal and vertical secondary aiming mark indicates 1 milliradian from an adjacent secondary aiming mark.
18. The riflescope of claim 13, wherein the thickness of the horizontal and vertical secondary aiming marks is approximately equal to the thickness of the primary horizontal and vertical sight lines.
19. The riflescope of claim 13, wherein each horizontal and vertical long range aiming mark indicates less than 0.5 milliradians from an adjacent long range aiming mark.
20. The riflescope of claim 19, wherein each horizontal and vertical long range aiming mark indicates 0.2 milliradians from an adjacent long range aiming mark.
21. The riflescope of claim 13, wherein the thickness of the horizontal and vertical long range aiming marks is approximately equal to the thickness of the primary horizontal and vertical sight lines.
22. The riflescope of claim 12, wherein the primary aiming point is transparent.
Type: Application
Filed: Feb 16, 2005
Publication Date: Nov 24, 2005
Applicant: Leupold & Stevens, Inc. (Beaverton, OR)
Inventors: Sergey Zaderey (Beaverton, OR), Andrew Evans-Hendrick (Norfolk), Andrew York (Portland, OR)
Application Number: 11/060,207