US 3826012 A
A gun sight which is adjustable to introduce a variable 'elevation' correction into the sighting of a target, and which has a scale or scales reading directly in terms of the proper gun to target distance for any particular setting of the sight.
Description (OCR text may contain errors)
@niee fiaies afieni Pachmayi' .Eufly 30, 1974 DIRECT READING GUN SIGHT 1,801,009 4/1931 Karnes 33/235 1,970,623 8/1934 Redfield 33/258 ADJUSTMENT 2,345,553 4/1944 Brown et a1. 33/259 Inventor: Frank Pachmayr, 2845 Medlll 3,297,389 1/1967 Gibson 33/245 PL, LOS Angeles, Calif. 90064 3,568,323 3/1971 Lendway 33/265  Filed: Dec. 28, 1971 Primary ExaminerLouis R. Prince [211 Appl 212929 Assistant Examiner-Steven L. Stephan Attorney, Agent, or Firm-William P. Green  11.8. C1 33/246, 33/233, 33/254, 42/15, 116/133  1nt.Cl. ..F41g 1/16, F4lg 1/38,F41g l1/00 ABSTRACT 58 Field of Search 33/247, 248, 246, 254, 1 933/252, 257, 258 259 260, 255, 256 241, A gun s1g1 1t Wh1Ch 1S acl ustable to Introduce a varlable elevanon correcnon into the slghtmg of a target, and 242, 243, 249, 233, 42/15, 116/133 WhlCh has .a scale or scales readlng d1rect1y 1n terms of  References Cited ggftigrogghgusrii gt) target distance for any particular UNITED STATES PATENTS g g 1.386.027 8/1921 Reynolds 33/248 12 Claims, 16 Drawing Figures SHEET 3 0? 3 lob DAJK A. Pawn 24v? INVENTOR.
DIRECT READING GUN SIGHT ADJUSTMENT BACKGROUND OF THE INVENTION This invention relates generally to adjustable gun sight structures, and particularly to improved elevation adjustments for such sights.
In conventional gun sights of a type having an elevation adjustment, the elevation setting is normally indicated and read out in terms of minutes of angle. Unfortunately, however, the proper angular correction varies for different target distances, and a person using the gun must, therefore, re-estimate or recalculate the proper angular correction every time that he changes the range at which he is firing. This necessity for thus repeatedly re-estimating the proper correction angle under what may be continually changing range conditions is extremely inconvenient, and may, in hunting, introduce just enough delay in firing to allow the prey to escape before a shot can be fired.
SUMMARY OF THE INVENTION The present invention overcomes the above discussed disadvantages of prior sight correction systems, by enabling the elevation adjustment of the sighting element to be read directly from the device in terms of gun to target distance, rather than in minutes of angle. Thus, if the target is for example 150 yards away, the user merely adjusts the sight to a predetermined 150 yard setting and is then ready to fire. At any subsequent time when the target is closer or farther away, a readjustment can be made to an appropriate changed distance setting, in extremely rapid fashion and without the necessity for any type of calculation or conversion of readings.
Optimally, the device has several different elevation scales, all reading directly in terms of gun to target distance, but offset relatively to a predetermined extent adapting the different scales for use with different types of ammunition. In addition, these scales may be designed for easy detachment from the apparatus, and replacement by one or more other similar scales adapted for direct reading with other different types of ammunition. As will appear, the scales may be retained by appropriate interfitting shoulders on a scale carrying part and a body of the sighting device, with these shoulders being shaped to allow an initial sighting-in adjustment of the scales.
Certain additional features of the invention relates to an adapter structure constructed to permit attachment of a scale or scales embodying the invention to a conventional sight assembly.
BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and objects of the invention will be better understood from the following detailed description of the typical embodiments illustrated in the accompanying drawings, in which:
FIG. I is a perspective representation of a gun having a telescopic sight embodying the invention;
FIG. 2 is an enlarged vertical transverse section taken on line 2-2 of FIG. 1;
FIG. 3 is a horizontal section taken on line 33 of FIG. 2;
FIG. 3a is a developed view showing the scale element proper of FIG. 3 separately and in flattened condition to better illustrate its three different scales;
FIG. 4 is a view similar to FIG. 2, but showing a variational form of the invention;
FIG. 5 is a similar view of another variational form of the invention;
FIG. 6 is a horizontal section taken on line 66 of FIG. 5;
FIGS. 7 and 8 are views similar to FIGS. 5 and 6, but showing another form of the invention;
FIGS. 9, I0, and II are views similar to FIG. 2, but showing three other forms of the invention;
FIG. 12 is a perspective view showing a nontelescopic type of gun sight constructed in accordance with invention;
FIG. 13 is a perspective view showing the vertically movable portion of the FIG. I2 device removed from the mounting element;
FIG. 14 is a horizontal section taken on line 14-14 of FIG. 12; and
FIG. 15 is a vertical section taken on line 15l5 of FIG. 12.
DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference first to FIG. I, I have illustrated at 10 a rifle having a telescopic sight 1 I mounted to its barrel 12. Sight 11 may be connected to the barrel in any appropriate manner, as by means of a bracket 13 hinged at 14 to swing about an axis 15 parallel to barrel 12 between the full line active sighting position of FIG. 1 above the barrel and the laterally and downwardly swung broken line inactive position at a side of the barrel. The sight proper 11 includes a tubular body 16 carrying appropriate lenses enabling a person using the gun to view the target area telescopically, and typically including an objective lens mounted at the forward end 17 of the tube, an ocular lens 18 carried at the rear. end of the tube, and an appropriate image inverting lens positioned at an intermediate location within the tube. The telescopic sight also contains a suitable reticle unit such as that typically illustrated at 19 in FIGS. 2 for loeating on the viewed area the precise point 20 at which the gun is aimed. Unit 19 is disposed in a plane which is perpendicular to the axis 21 of the telescopic sight, and in which plane the viewed image of the target area is in focus. In FIG. 2, unit 19 is represented as including a rigid peripheral ring 22 carrying a vertical crosshair 23 and a horizontal crosshair 24 intersecting at the central point of aim 20. Unit 19 is movable upwardly and downwardly in FIG. 2 to raise and lower the point of aim 20 relative to the viewed target area, thereby attaining an elevation adjustment or correction of the sight; and is also movable leftwardly and-rightwardly in FIG. 2 to shift the point of aim horizontally with respect to the viewed target area, and thereby attain a windage adjustment.
For effecting the elevation and windage adjustments of reticle unit 19, there is mounted on tube 16 of the telescopic sight an adjusting assembly 25, which may include a rigid typically metal body or saddle 26 extending partially or completely about tube 16 and appropriately secured thereto in fixed relative position as by suitable screws (not shown). An elevation adjusting control element 27 is mounted to turn about a vertical axis 28 relative to tube 16 and the body 26, and may have an externally threaded shank portion 29 threadedly engaging tube I6 at 30 to cause upward and downward movement of the element or knob 27 upon rotation about axis 28. At its lower end, the threaded shank 29 acts downwardly against ring 22 of the reticle unit 19, typically through a horizontal bearing plate 31, to adjust the unit 19 upwardly and downwardly in accordance with rotation of element 27. A leaf spring 32 or other appropriate means are provided for resisting downward movement of unit 19, and returning that unit upwardly upon upward movement of element 27. To enable rotary actuation of element 27, the upper surface of enlarged diameter portion 33 of that element may contain a screw driver slot 34 (see FIG. 3), which is adapted to receive a screw driver, coin, or the like in turning element 27.
At its upper side, body 26 carries part 35 which may be integral with the body or be secured thereto in rigidly fixed position, and which has an upwardly projecting essentially annular flange portion 36 provided on its outer surface with external threads 37 centered about vertical axis 28. At the upper extremity of this flange portion 36, part 35 has an annular radially inwardly projecting rib 38.
To flange portion 36 of part 35, there is mounted an adapter element 39, having a reduced diameter portion 40 containing an internal thread engageable with external thread 37 of flange 36. At the upper end of this portion 40, adapter 39 has an annular radially outwardly extending horizontal portion 42, terminating in an upwardly extending portion 43 having external threads to which the internal threads on a dust cap 44 are connected. Within adapter 39, there is adjustably mounted a scale assembly 45, which is annular about axis 28 except at the location of an interruption 46 at one location about its periphery (see FIG. 3). The scale assembly includes a main essentially annular element 47 and a scale element proper 48, both of which are interrupted at the location 46. Element 47 has the cross section illustrated in FIG. 2, defined in part by a horizontal undersurface 49 supported on the horizontal portion 42 of adapter 39, and a cylindrical external surface 50 received within and confined by the upstanding portion 43 of adapter 39. Above flange 43, the part 47 may have an essentially annular series of knurls or serrations 51 accessible for manual grasping to turn element 47 relative to adapter 39 and control element 27. The scale element proper 48 may be carried on an inclined annular inner surface 52 of element 47, and have its upper and lower edges confined within suitable essentially annular notches or grooves in part 47 to removably hold element 48 in fixed position relative to part 47.
At its radially inner extremity, part 47 has an essentially annular downwardly projecting portion 53, carrying an essentially annular radially outwardly projecting rib 54 receivable beneath rib 38 of part 35 to hold part 47 against upward movement from the FIG. 2 position, while at the same time guiding that part 47 for only rotary motion, about vertical axis 28, relative to adapter 39 and parts 26 and 35. Part 47 is resiliently deformable to a constricted reduced diameter condition, by squeezing the part 47 at knurls 51 to close gap 46. In this constricted condition, rib 54 has a small enough diameter to move upwardly past rib 38 and thereby allow removal of element 47 and part 48 from the rest of the device. When in its FIG. 2 installed condition, part 47 is urged by its own resilience radially outwardly against the inner surface of upstanding flange portion 43 of adapter 39, with sufficient force to frietionally retain element 47 in any set position to which it may be manually turned. The part 47 may, however, be forceably adjusted rotatably against the resistance offered by this frictional engagement, either with or without slight manual constriction of part 47 to partially or completely relieve the frictional contact.
FIG. 3 shows in developed or flattened form the type of indicator markings which are provided on the scale element 48. These markings desirably include several, typically three, scales 56, 57, and 58, coacting with an index marking 59 on control element 27, with each of the scales reading directly in terms of the proper gun to target distances for the different settings of element 27. With reference for example to the scale 56 of FIG. 3, the markings I00," 200, etc. of that scale represent different target distances of yards, 200 yards, 300 yards, etc., from the gun to a particular target being fired at. When index marking 59 is opposite a particular one of these markings, this indicates that the telescopic sight has been adjusted for an elevation correction which is exactly proper for that particular firing distance.
The three scales 56, 57, and 58 give proper range readings in this manner for three different types of ammunition, say for example ammunition having three different bullet weights, all of the same caliber. In the typically illustrated arrangement, the marking at 60 in FIG. 3 indicates that the scales are for use with a 270 Winchester" caliber gun, with scale 56 being applicable to bullets of that caliber having a weight of 100 grains, as indicated at 61, while the markings of scale 56 apply to bullets of the specified caliber having grains weight (see 62), and scale 58 applies to bullets of grains weight but still of the same caliber (see 63). If a bullet or bullets of other calibers or weights are to be employed, the part 48 may be removed and another similar part of different markings may be connected to element 47. At a location opposite the markings 61, 62, and 63, element 48 may carry a shiftable indicator button or marker which is slidable within a radial slot 161 in part 48 to positions opposite the three markings 61, 62, and 63 selectively, and is frictionally retained in any position to which it is set, to remind the user which of the three indicated types of ammunition is being used.
The windage adjustment of reticle unit 19 may be effected by a mechanism including a control element 65 similar to the elevation controlling element 27, threadedly engaging tube 16 and/or body 26 at 66, and acting through a bearing plate 67 to actuate unit 19 rightwardly in FIG. 2 against the influence of a return spring 68. An appropriate scale 69 surrounding element 65, reading in minutes of angle, coacts with an index marking or element 65 to indicate the windage correction angle which is attained at any particular setting of element 65 and unit 19.
When the telescopic gun sight of FIGS. 1 to 3 is first mounted on a gun, the device must of course be initially sighted in in order to adjust the scale part 48 to a proper rotary setting relative to adapter 39. For this prupose, the user of the gun fires a number of cartridges of a known caliber and weight (a caliber and weight for which there is a scale on element 48), with all of those cartridges being fired at a particular measured distance from the target, say for example 100 yards, and all desirably being fired when there is no wind in the vicinity. The control elements 27 and 65 are then adjusted until the gun, when fired at the specified range, consistently hits the exact target location at which the reticle intersection is aimed. In this setting, the sight is properly corrected for elevation at that 100 yard firing distance. With the telescopic sight thus set, element 47 and its carried scale part 48 are manually constricted very slightly and turned within adapter 39 to a position in which the I00 yard marking on the appropriate one of the three scales 56, 57, or 58 is directly opposite the index marking 59 on element 27. Thereafter, the scale is frictionally retained in this position, in which all of the other markings on the three scales are automatically located properly to give correct target distance readings for the particular types of ammunition for which the three scales have been calibrated.
FIG. 4 shows a variational arrangement which is very similar to that of FIGS. 1 to 3, except that the adapter 39 is omitted, and the scale carrying element 47a and the scale element proper 480 are connected directly though adjustably to the upstanding flange portion 36a of stationary part 35a. More particularly, element 47a has a downardly projecting portion 53a forming an annular rib 54a receivable beneath an inturned annular rib 38a formed at the upper edge of flange 36a, to retain element 47a in the FIG. 4 position relative to tubular body 16a of the telescopic sight, while allowing rotary adjusting movement of element 47a and the carried element 48a about vertical axis 28a of rotary control element 27a. Parts 47a and 48a are interrupted at 46a as in the first form of the invention, to enable constriction of these parts to a condition in which they are upwardly removable from the rest of the apparatus when desired. As in the first form of the invention, the resilience of part 47a urges it radially outwardly against flange 36a of part 350 sufficiently tightly to retain element 47a frictionally in any position to which it may be set, but with part 47a and the carried part 48a being forceably adjustable rotatably to any new setting by manual grasping and slight constriction of the knurls 51a on part 47a. The scale markings on element 48a are the same as those shown in FIG. 3, resding directly in terms of gun to target distance, so that the user can set the sight very easily, quickly and directly for any particular range without the necessity for calculating or estimating a proper correction in terms of angles rather than distances.
The adjustable sight element 19a of FIG. 4 which is actuable upwardly and downwardly by control element 27a, and is actuable laterally for windage adjustment by a second control element 650, is typically illustrated as taking the form of a lens 70 contained within and carried by an annular ring 71. In this arrangement, the reticle corresponding to crosshairs 23 and 24 of FIG. 2 is located at another point along the length of the telescopic sight, and is fixed relative to and not adjustable relative to that tube. The apparent position of the crosshair intersection relative to the telescopically viewed target area in FIG. 4 is shiftable by the discussed movement of lens 70 under the control of elements 27a and 65a. This type of arrangement in which the adjustable sight element is a portion of the lens system is well known, and therefore will not be described in any further detail. In FIG. 4, the dust cover 44a may be threadedly connected to the external threads on flange 36a, and extend upwardly past and in close proximity to knurls 51a of element 470. The operation of the FIG. 4 arrangement is the same as that of FIGS. 1 to 3.
FIGS. 5 and 6 show another form of the invention in which the element 47b corresponding to element 47 of FIG. 2 extends horizontally across the upper side of part 35b, having a downwardly projecting portion 53b with a radially projecting essentially annular rib 54b interfitting with an annular rib 38b on part 35b to retain element 47b as previously discussed. At its upper side, element 47b carries a removable scale part 48b, whose inner and outer edges may be confined within suitable confining notches or grooves in part 47b. Element 48b has at its upper side a number of target distance scales such as those shown at 56, 57, and 58in FIG. 3, and has at its underside a second series of different scales (still all marked off in distances), so that element 48b can be inverted as desired to present any of the various scales on either of its sides for coaction with the index marking 59b on control element 27b. Element 48b has some resilience to tend to assume a flattened condition and thereby remain by its own resilience in the retained condition of FIG. 5.
In FIGS. 5 and 6, the control element 27b has been altered to present an upper reduced diameter portion 74 about which elements 47b and 48b are receivable, to thus allow for greater radial extent of the scale part 48b and thereby enable inclusion of more scales thereon. Also, parts 47b and 48b are interrupted as in the other forms of the invention at 46b, and may be constrictable inwardly for removal by providing upwardly projecting finger tabs 75 on the opposite ends of element 47b adapted to be easily squeezed together to constrict that element. The dust cover 44b is threadedly connectible to part 35b at 37b, and extends about and encloses the scale parts and control element 27b. As in the other forms of the invention, the resilience of part 47b holds it against part 35b sufficiently tightly to retain the scale frictionally in any position to which it may be set.
FIGS. 7 and 8 show still another form of the invention, which may be essentially the same as that of FIG. 4 except that the scale element 47c is of the illustrated changed configuration. Element 470 has a reduced external diameter vertically intermediate portion 76 forming a groove receiving an annular rib 380 of part 35c, to locate part 47c for rotary adjustment about a vertical axis 280. Element 476 is interrupted at 46c, permitting sufficient constriction thereof against its resilience to allow its removal and inversion between either of two positions, so that either of the two ribs 77 or 78 may be located at the upper side of the device. Two sets of finger tabs 75c and 75cc are accessible in these two relatively inverted positions respectively of element 470, to enable manual constriction of that element to its removal condition, or to a slightly reduced diameter condition for releasing the frictional lock be tween element 470 and part 350 and facilitating rotary adjustment of element 470. Two different sets of target distance scales are provided on the two surfaces 79 and 80 of part 47c, for coaction with index marking 59 c on rotary control part 27c, so that in either of its inverted conditions, the scale part 470 may be employed with appropriate selected types of ammunition for indicating directly the proper elevation correction for any given target distance.
In the FIG. 9 arrangement, part 47d is flat and disposed horizontally and is essentially annular except at the location of an interruption 46d at which upwardly and downwardly directed finger tabs 75d are provided to facilitate constriction of element 47a to withdraw its circular peripheral edge 83 out of an annular groove 81 formed in adapter 39d beneath an annular rib 82d. As will be apparent, the part 47d is usable in either of two relatively inverted positions, and may have two series of different scales on its upper and lower surfaces 84 and 85, with one of these series of scales giving the proper target distances for a number of different bullet weights at a predetermined caliber, while the other series of scales gives the proper target distances for another group of bullet weights still typically at the same caliber. The dust cover 44d is threadedly connected to adapter 39d at 86, by threads which in this instance may typically be of the quarter turn quick disconnect type.
In the FIG. arrangement, the annular peripheral edge of element 47e is again confined and located within an annular groove 81e formed in adapter 39a, and is circularly discontinuous at 46c and constrictable for rotary adjustment or removal from the groove by finger tabs 75e. A scale element 48e has a number of direct reading target distance scales similar to scales 56, 57, and 58 in FIG. 3a. The dust cover 44@ in FIG. 10 is represented as hinged at 87 to swing upwardly and laterally to a position exposing the scales and control element 27e for use, with the cover being releasably retained in closed position by an appropriate latch represented at 88.
The FIG. 11 arrangement is substantially the same as that of FIGS. 1 to 3, except that element 47f extends essentially horizontally and carries scale element 48fin a generally horizontal though bowed condition, retained at its edges 89 within appropriate essentially circular notches in part 47f, and being removable and reinsertible in an inverted position exposing a second series of scales on element 48ffor use. Finger tabs 75f allow constriction of element 47f at 46f, to release the essentially annular rib 54f from beneath rib 38f for removal.
FIGS. 12 to 15 show another variational type of gun sight 90, which in this case is of a non-telescopic type, having a peep sight element 91 containing a small opening 92 through which a forward gun sight 93 is viewed, in a manner aligning the sights on a target to aim the gun. The assembly 90 includes a mounting part 94 which is suitably secured to gun action 95 in fixed position relative thereto, as by a screw or screws 96, and which contains a vertically extending dovetail guideway 97 within which a correspondingly dovetail shaped vertical portion 98 of a part 99 is received and guided for upward and downward movement along a vertical axis 100. At the upper end of portion 98, part 99 has a horizontally projecting portion 101 to which the peep sight 91 is mounted for lateral adjusting movement transversely of the sighting axis 102 in response to rotation of an adjusting screw 103, which threadedly engages element 91 and has a head 203 by which the screw is turned manually or by a screw driver or other tool. The lateral position or windage adjustment of the peep sight may be indicated by the setting of an index marking 104 on the peep sight element relative to a windage scale 105 on part 99.
For indicating the vertical position of the peep sight relative to the gun barrel, and thus indicating the elevation setting of the device, mounting part 94 carries an index marker 106 coacting with a series of elevation scales 107, 108, and 109 formed on the front face of a scale part 110 which may be removably attached to portion 98 of element 99. More particularly, this part 110 may be received within a horizontally extending dovetail guideway 111 (FIGS. 13 and 15) formed in vertical portion 98 of part 99. As will be apparent, the engagement of upper and lower dovetail faces 112 and 113 of part 110 with the corresponding dovetail faces 114 and 115 of portion 98 of part 99 guide element 110 for only horizontal movement relative to portion 98, parallel to barrel axis 202. Further, when portion 98 and part 110 are received within the vertical dovetail recess or guideway 97 in mounting part 94, part 110 is effectively locked in fixed position within horizontal guideway 111 and against removal therefrom. For this purpose, the part 110 has at its opposite sides (as viewed in FIG. 14) two dovetail shaped faces 116 and 117 which are disposed at an angle corresponding to and are aligned with the dovetail faces 118 and 119 of portion 98 of part 99, and are engageable with the dovetail shaped side walls 120 and 121 of guideway 97 to lock part 110 in position. The three scales 107, 108, and 109 on part 110 extend vertically and parallel to one another, and may correspond to the three scales 56, 57, and 58 of FIG. 3a, to indicate the elevation settings of sight 91 in terms of gun to target distance, and for three different types of ammunition, such as the three different weights of bullet indicated at 61, 62, and 63 in FIG. 3a. The types of ammunition for which the three scales are usable may be appropriately marked at the tops of the scales. Additional similar scales for use with other types of ammunition may be provided on one or more other elements such as that shown at 110, which may be substituted for one another by merely sliding part 99 upwardly far enough to expose the entire horizontal dovetail guideway 111, and then sliding that part 110 out of guideway 111 and inserting another similar part, following which the entire assembly may be moved downardly to the FIG. 12 position for use. If desired, still another part 110 may be provided reading more conventionally in terms of minutes of angle rather than in terms of gun to target distance as contemplated by the present invention.
The vertical elevation adjustment of part 99 is effected in use by rotation of a knob 122 carrying a downardly projecting threaded screw or shank 123 which may be releasably engageable with a half-nut 124 formed on apart 125 carried movably by mounting element 94. As seen in FIG. 14, this half-nut 124 is actuable leftwardly in that figure out of engagement with the adjusting screw shank 123 by manual leftward depression of an operating head 126 against the tendency of a spring 127. When the element 124 is moved leftwardly out of engagement with shank 123, the entire element 99 may be withdrawn upwardly for removal of one of the parts 110 and substitution of another, after which the entire assembly can be pressed downwardly again into guideway 97, and element 126 can then be released to allow half-nut 124 to move into engagement with shank 123 so that rotation of knob 122 will effect the desired vertical adjustment of part 99.
While certain specific embodiments of the present invention have been disclosed as typical, the invention is of course not limited to these particular forms, but rather is applicable broadly to all such variations as fall within the scope of the appended claims. Any of numerous other types of both telescopic and nontelescopic sights can be adapted to give elevation settings in terms of gun to target distances in a manner similar to the arrangements specifically described hereinabove.
1. in a gun sight structure including telescopic sighting means having an adjustable sight element which is movable in a predetermined direction to introduce a variable elevation correction into the sighting of a target, a rotary adjusting part mounted to be turned about a predetermined axis and operable upon rotation to move said element to a series of different elevation settings, and a second part near said rotary adjusting part and which does not turn therewith; the improvement comprising a plurality of scale members, means for detachably connecting said scale members selectively and interchangeably to one of said parts at a location to coact with index means associated with the other part in indicating elevation, different caliber markings on said different scale members respectively indicating different caliber bullets for which said members respectively are to be used, a plurality of essentially arcuate scales formed on each of said scale members and each reading directly in terms of proper gun to target distances for which said rotary part is adjusted in different settings thereof, said scales of each scale member being staggered circularly about said axis in a relation giving gun to target distance readings for bullets of different weights respectively but all of the same particular caliber identified by the one of said caliber markings which is on that particular scale member, and additional marking means on each of said scale members indicating said different bullet weights for which each of said scales is to be used.
2. The improvement as recited in claim 1, in which said connecting means are constructed to attach each of said scale members to said one of said parts in a relation enabling initial sighting-in adjustment of the scale members about said axis relative to said one part, with ultimate retention in a desired adjusted position.
3. The improvement as recited in claim 1, in which said scale members are essentially circular to extend essentially circularly about said axis in use.
4. The improvement as recited in claim 1, in which said scale members are essentially circular and have portions interfitting with said one part in arcuate projection and groove relation, said scale members being circularly discontinuous and resiliently distortable radially of said axis in a relation moving said interfitting portions into and out of interfitting relation to attach an individual one of said scale members to or detach it from said one part.
5. The improvement as recited in claim 1, including an essentially circular carrier disposed about said rotary adjusting part for attaching one of said scale members to said second part, said carrier and said second part having interfitting essentially arcuate shoulders mounting said carrier to said second part for relative adjusting movement and frictional retention in a desired adjusted position, said carrier being circularly discontinuous and resiliently radially distortable to a condition in which it is separable from said second part.
6.' The improvement as recited in claim 5, in which said carrier has an irregularized external surface exposed for contact by a users fingers in turning the carrier relative to said second part.
7. The improvement as recited in claim 1, in which said second part has a tubular portion with external threads and an internal arcuate shoulder, there being an adapter having a reduced diameter portion with internal threads engaging said external threads of said tubular portion of said second part, said adapter having an enlarged diameter portion, there being a carrier member disposed about said rotary part and received within said enlarged diameter portion of said adapter and rotatably adjustable relative thereto and having an arcuate flange engaging said arcuate shoulder of said second part, said carrier being adapted to carry one of said scale members in a position of extension about said rotary part, said carrier being circularly discontinuous and resiliently radially constrictable to a condition allowing removal thereof from said tubular portion of said second part.
8. The improvement as recited in claim 7, in which said carrier has an irregularized external surface beyond said enlarged diameter portion of said adapter exposed for manual actuation, said enlarged diameter portion of said adapter having external threads, and there being a dust cover connected to said external threads and enclosing said rotary part.
9. The improvement as recited in claim l, in which said second part has a tubular portion disposed about said rotary part and having external threads, there being an adapter having a reduced diameter internally threaded portion engaging said external threads of said second part, said adapter having a larger diameter portion within which said scale members are detachably and interchangeably mountable by said connecting means.
10. The improvement as recited in claim 9, in which said connecting means include an essentially circular but circularly discontinuous carrier to which said scale members are connectable and which is resiliently constrictable to a reduced diameter condition for attachment to and separation from said second part and adapter.
11. The improvement as recited in claim 1, in which said scale members are essentially circular and circularly discontinuous and resiliently radially constrictable to conditions enabling attachment to and detachment from said one part, said discontinuous essentially circular members having tabs at their opposite ends for constricting said members radially.
12. In a gun sight structure including an adjustable sight element which is movable in a predetermined direction to introduce a variable elevation correction into the sighting a target, a movable adjusting part operable to actuate said element to a series of different elevation settings, and a second part near said adjusting part and which does not move therewith; the improvement comprising a plurality of scale members, means for detachably connecting said scale members selectively and interchangeably to one of said parts at a location to coact with index means associated with the other part in indicating elevation, different scales formed on said different scale members respectively and each reading directly in terms of proper gun to target distances for which said adjusting part is set in different positions thereof, said scales of the different members being calibrated to give gun to target distance readings for different types of ammunition, and markings on said scale members indicating said different types of ammunition with which the different scale members are used.