US3492750A - Muzzle choke - Google Patents

Description

- Feb. 3, 1970v `A SHBOOK Em. 3,492,750

MUZZLE CHOKE Filed Nov. 15, 1967 2 sheets-sheet 2 Alvor/ver' 3,492,750 MUZZLE CIIOKE Clifford Logan Ashbrook, 5027 Cheena 77035, and Wilson Gordon Wing, 33 E. Rivercrest 77042, both of Houston, Tex.

Filed Nov. 15, 1967, Ser. No. 683,200 Int. Cl. F41f 17/12 U.S. Cl. 42-79 11 Claims ABSTRACT F THE DISCLOSURE A shot diverter for use with a shotgun and in which the diverter includes upper and lower walls and side walls. The upper and lower walls converge from rear to front. Likewise the side walls converge from rear to front but at an angle with respect to each ,other which is different from the angle which the upper and lower walls converge towards each other. A plurality of Shot diverting ridges are integrally disposed on the walls and oriented in a generally rear to front manner.

This application constitutes a continuation-in-part of our prior co-pending application tiled Aug. 14, 1967, and bearing Ser. No. 660,446.

Background ,of the invention The present invention relates to a muzzle device for use with firearms and, more particularly, firearms of a shotgun variety.

It is desirable in a variety of firearm applications to produce a shotgun shot pattern of elliptical form with the major axis thereof residing in the horizontal plane and the minor axis in the vertical plane. Such a shot distribution is found to have considerable value in numerous and varied applications such as game hunting, guerilla warfare, and civil riot control. The primary advantage of such a shot distribution pattern is obvious, that being a much higher probability of striking the intended target with the missiles of the firearm.

Although numerous attachments, chokes, and other forms of shot-shaping devices have been designed heretofore for utilization with the muzzle of a shotgun, none have adequately and reliably solved the problem of predetermined shot distribution. Such devices are generally bulky, difficult and/or dangerous to use, and do not provide results in accorance with the intended or desired purpose. The problem has been engaged from a number of viewpoints by the prior art including the utilization of gas relieving apertures in the muzzle device for venting explosion gases quickly to atmosphere in a manner similar to the 'present invention, laterally extending slots in the wall of the shotgun bore or in the walls of an attachment thereto for permitting horizontal expansion of the shot pattern upon tiring (United States Patent No. 3,226,871), and a wide variety of conventional and rather unconventional choke designs. Although certain of these devices have, in fact, tended to achieve some predetermined pattern of shot, the pattern has not been reasonably predictable, nor has the success in achieving such a pattern been consistent over va plurality of firings. The devices themselves have, at times, proven dangerous, due to their tendency to fracture after a number of repeated firings. It is these shortcomings and deficiencies which has occasioned and motivated the present invention.

This invention constitutes a first recognition of the sophisticated requirements necessary for achieving controlled distribution of the missiles of a shotgun shell. There is described herein a cage and diverter device working cooperatively to both vent specific types of gases from the bore of a shotgun, while at the same time permitting States Patent ICC the conventional choking action in conjunction with .other structures for producing a predetermined distribution of shot upon a remote target. The invention, therefore, not .only obviates the primary obstacle to which prior art devices have been directed but, in addition, provides a structure which is both reliable and safe; and which is easy to handle, simple in operation, eicient in use, and relatively inexpensive to manufacture. These, and numerous other features and advantages of the invention, shall become more readily apparent to the reader upon examination of the following detailed description, claims, and drawings, wherein like numerals denote like parts in the several views, and wherein:

FIGURE l shows in perspective a preferred form of the invention.

FIGURE 2 shows the diverter and cage sections of FIGURE l removed from each other and viewed obliquely from the rear thereof.

FIGURE 3a illustrates schematically a rst position of a shotgun shell as it traverses the bore.

FIGURE 3b illustrates a second position of a shotgun shell as it traverses the bore toward the cage aperture showing also the forms of gasses acting upon the wad of the shell.

FIGURE 3c shows a third position of the shell as it traverses the bore and after the wad has substantially passed the cage aperture of the section of the subject invention.

FIGURE 4a illustrates a front view or the exit end of the invention of FIGURE 1.

FIGURE 4b illustrates a sectional view of the diverter of FIGURE 2 along the plane 4 4 thereof.

FIGURE 5 is a vertical sectional view along the plane 5 5 of FIGURE 4a.

FIGURE 6 is a horizontal sectional view along the plane 6 6 of FIGURE 4a.

With reference now to FIGURES l and 2 of the drawing, there is shown in preferred form, but for exemplary purposes, the diverter 5 and cage sections 3 of the invention. The diverter is characterized by an elongated cylindrical like body having a right side wall 11 and left side wall 13 opposite one another. Although the diverter is of generally frusto-conical configuration, its upper and lower surfaces are machined to define the upper wall 7 and lower wall 9. Machining of these walls tends to reduce the `overall weight of the diverter section thus making it easier to handle. Machining such surfaces also tends to maintain substantially constant wall thickness throughout the longitudinal length of the diverter, thus reducing the tendency towards creation of differential metal pressures and fatigue created by elevated temperatures. The rearward portion of the diverter tube 5 is characterized by the threaded end connection 27 which has a reduced diametrical dimension by comparison to the rearward end of the right and left walls 11 and 13 respectively. The magnitude of the difference in diameter is illustrated by the diverter flange wall 37 which mates in intimate contact with the front wall 39 of the cage member 3.

Cage member 3 is of generally cylindrical configuration, having an elongated central bore 40 axially aligned with the diverter bore 41 described hereinafter. The elongated central bore 4t) is characterized by the internal threaded connection 31, 32 at the exit and entry ends thereof respectively. The threaded connection 31 at the exit end of the cage is of such predetermined internal diameter as to cooperatively receive and engage a threaded connection 27 of the diverter tube S. The cage member 3 further includes a plurality of apertures circumferentially disposed about the surface thereof, the apertures being defined by the longitudinal aperture walls 15, 17 (see FIGURE 1) and the rearward and forward lateral aperture walls 19, 21 respectively. The four walls intersect to form a plurality of the apertures such as three as is shown in the illustration. The longitudinal aperture walls 15, 17 are of planar type surface except at the forward corners thereof, where a fillet or corner curved surface 23 is provided so as to form a smooth intersection with the forward lateral walls 21. These fillets or grooves on the comers of the cage vertical and horizontal walls serve to enhance turbulence of escaping gases upon the passage of a projectile through the cage member. Such turbulence lowers the pitch of audio-type waves, thus causing a very substantial reduction in the overal noise level when the weapon is fired.

As is best shown in FIGURES 3a through 3c, the diverter and cage of the invention are ordinarily affixed to the end of a muzzle, such as that of a shotgun. In FIGURE 3a there is shown the position of a typical wad 24 of a shotgun shell as it approaches the apertures of the cage member 3 subsequent to firing. Prior to the time at which the shell reaches the aperture, there of course can be no escape of any of the gases behind the shell. Upon intersection of the wad with the aperture, there is created an immediate release of the gas pressure behind the wad. It has been found in accordance with this invention that the gases following the wad as it passes through the cage and diverter may be generally considered to be either of the hard gas variety or the soft gas variety. The hard gas is generally -of a laminar fluid species while the soft gas is more turbulent in nature. In accordance with the invention, it is further known that as the rear wall of the wad opens from the rear lateral wall 19 of the aperture, the gases following the wad are emitted into the aperture at an initial expanding angle which varies from degrees, 8 minutes to 6 degrees, 0 minutes. It will, of course, be recognized that these gases 49 are primarily of a soft gas nature and at the time of their initial escape tend to increase the recoil reaction on the muzzle. AS these gases expand forwardly, however, they come into contact with the forward lateral aperture wall 21 and react thereon, thus tending to reduce the recoil reaction of the weapon. In order to maximize the effect of the impinging gases upon this wall, the wall itself is constructed at a six degree (6) angle (or less) with respect to a plane running perpendicular to the longitudinal axis of the diverter tube. The diverter tube rear wall 29 is similarly sloped at an angle alpha, or in the maximum case, six degrees (6), since this wall constitutes an extension of the forward lateral wall 21 of the aperture when the diverter tube is threaded into the cage member. It will thus be seen that the angle alpha is so calculated as to create a surface which is perpendicularly oriented with respect to the impact points of the soft gas 49. The forward lateral wall 21 of the aperture is likewise so oriented. The reason for the angular deflection of gases as explained above lies in the creation of the hard gas characteristic or laminar gas layers 43 discovered as an incident to this invention. The hard gas 43 proceeds behind the shell wad 24 and is of generally conical shape. The conically shaped hard gas or concentrated gas molecules act as a deecting cone for gases following therebehind, thus causing such gases to be defiected outwardly at the angle disclosed above. These following gasses create a pulsing reaction on the forward lateral aperture wall 21. This pulsing action is found to account for a signicant increase, of up to five percent in the shell velocity. An advantage of this is the improved pattern predictability which results. A further advantage of the specific aperture structure of the cage member 3 resides in the substantial absence of any flash either at the exit end of the diverter tube S or at H the apertures of the cage member 3, upon firing. This may be explained by the stacking effect of the heated gases (FIGURE 3c) in the central bore of the cage member as the shell passes therethrough and by the calculated deflection of gases back towards the apertures.

This reflection of the soft gas flow tends to increase the gas temperature within the cage, thus elevating the pressure therein. As a consequence, the gases are ignited well within the bore of the cage member, rather than outside it, thus substantially eliminating the observance of any illumination upon firing of the weapon.

Reference may now be made to FIGURES 4a and 4b in conjunction with FIGURES 1 and 2. Here, there is shown the shot diverting ridges 51 for creating the predetermined pattern of shot upon a target all in accordance with the teachings herein. Although the diverter bore 41 is shown in FIGURE 1 to include three diverter ridges on each the upper and lower surface, it will be recognized that any number of diverter ridges can be utilized in the practice of this invention. The function of the semi-circular areas which characterize the diverter tube and which are defined by the diverter ridges 51 is to guide in a predetermined manner the shot pellets of a shell as they traverse the bore. Thus, in a bore for a #4 buckshot such as is illustrated in FIGURE 4a, there would reside in front of the wad Ysix (6) spherical pellets disposed in accordance with the cross-sectional pattern of the bore, there being one additional pellet behind the six and at the center thereof. Since the function of the bore, regardless of the number of pellets to be contained therein, is to reshape the shot distribution in a longitudinally expanded and vertically suppressed manner, the internal slopes of the bore are designed to accomplish this object. Thus, the upper and lower ridges 51(a) [FIGURE 4b] slope from the diverter rear wall 29 towards the central axis as they approach the front or exit end of the diverter tube. As shown in FIGURE 5, the slope may preferably range between l.5 to 3.5 degrees with respect to the horizontal. When viewed in the horizontal plane (see FIGURE 6), the bore likewise converges from the rear end to the front end so as to create the desired longitudinally elongated shot pattern. It is thus seen that the diverter in effect creates a volumetric change per unit of length or as might otherwise be described, volumetrically diminishes and expands the shot per unit of length or advance in the bore. It should further be pointed out that the interior surface of the diverter, or, more specifically, the bore thereof, need not be perfectly smooth as is the common practice. It has been learned in accordance with this invention that the surface may be intentionally roughened so as to disturb the shot as it traverses the bore. This tends to make the shot more amenable to shaping by reason of its constant bouncing and movement as it travels down the bore. In this manner substantially improved shot distribution patterns are achieved. A surface roughness of fifty (50) micro-inches to one hundred twenty-five microinches is recommended for this purpose. As best shown in FIGURE 4b and FIGURE 2, the central-upper and lower shot diverting ridges are more pronounced nearer the exit end of the diverter tube and, in fact, the ridges gradually merge into the upper and lower surface of the tube as they approach the diveter rear wall 29. Thus, as shown in FIGURE 2, these two diverter ridges therefore are not observable.

In operation, when a shell is fired, the spherical pellets contact the sloping sides 53, 55, 53a, 55a, and are vertically concentrated in an inward direction towards the horizontal plane in which the central axis lies. At the same time, the shot is compressed outwardly when viewed in the horizontal plane (FIGURE 6), this despite the fact that the sides 59, 57 converge from rear to front. There can, for example, be produced a uniformly distributed pattern of shot within a two (2) foot high by fifteen (15) foot wide rectangle at thirty (30) yards, compared to a conventional circular pattern of two 2) feet or less. The shell wad, even when of the relatively dense and heavy military type, passes through the reduced mouth area without damaging the shotgun due to the substantial and effective gas pressure relief provided by the aperture in the cage member 3.

It will be recognized that numerous and various modifications of the present invention may be made without departing from the spirit and scope thereof. For example, as previously mentioned, any number of shot diverting ridges could be utilized in accordance with an intended pattern. Similarly it will be recognized that, contrary to the teachings hereinabove, the upper and lower walls could be made to converge at an angular rate to the longitudinal axis which is less than that at which the side Walls converge with respect thereto. There would thus be obtained a vertically expanded, horizontally reduced pattern of shot when compared to the conventional shot distribution. It is considered feasible even to provide an incremental slot either in the side walls or the upper and lower walls of the diverter tube adjacent the diverter bore at theV front end thereof. Such a slot could be so calculated so as to expand the pattern either verticallyor horizontally in accordance with the desired result. Still other modifications within the spirit of the invention and the scope of the appended claims may occur to those skilled in the art,

Therefore, what is claimed and desired to be secured by United States Letters Patent is: t

1. A shot diverter for use with a shotgun for producing a vertically reduced-horizontally expanded pattern of shot distribution on a remote target comprising:

an elongate tubular body having an entry end, an exit end, and an imaginary longitudinal axis extending therebetween, the interior of said tubular body being defined by upper and lower wall means and side wall means, said upper and lower wall means being arranged to gradually converge from the entry end to the exit end, said side wall means being similarly disposed to gradually converge from the entry end to the exit end,

the angular rate of convergence of said side walls being smaller than said upper and lower walls so that the pattern of shot emerging from the exit end is concentrated more by the upper and lower walls than by the side walls to thereby produce the vertically reduced-horizontally expanded pattern of shot distribution, and

ridge means disposed on at least one of said wall means for influencing the direction of shot movement as it tranverses the body.

2. The shot diverter of claim 1 wherein said ridge means are disposed on the upper and lower wall means in diverging manner with respect to the imaginary longitudinal axis when viewed from the entry to the exit end of the body so as to further enhance selective movement of certain of the shot into a horizontally expanded pattern.

3. The shot diverter of claim 2 wherein said ridge means are disposed on said side wall means in converging manner from entry to exit end so as to enhance the direction of movement of certain of the shot into a vertically reduced pattern of distribution even though the shot may not be fully in contact with the upper or lower vWall means.

4. The shot diverter of claim 3 wherein said ridge means are most prounced at the exit end and become proportionately less pronounced per unit of length towards the entry end, thereby gradually sloping downwardly from the exit to the entry end so as to merge into the surface of said wall means proximate the entry end, and thereby providing for gradual but positive alignment of selective shot pellets into predetermined directions.

5. The shot diverter of claim 2 wherein said ridge means are most pronounced at the exit end and become less pronounced per unit of length towards the entry end,

6 thereby gradually sloping downwardly from the exit end to the entry end so as to merge into the surface of said wall means proximate the entry end, and thereby providing for gradual but positive alignment of selective shot pellets into predetermined directions.

6. The shot diverter of claim 1 wherein said ridge means are disposed on said side wall means in converging manner from entry to exit end so as to enchance the direction of movement of certain of the shot into a vertically reduced pattern of distribution even though the shot may not be fully in contact with the upper or lower wall means.

7. The shot diverter of claim 6 wherein said ridge means are most pronounced at the exit end and become proportionately less pronounced per unit of length towards the entry end, thereby gradually sloping downwardly from the exit end to the entry end so as to merge into the surface of said wall means proximate the entry end, and thereby providing for gradual but positive alignment of selective shot pellets into predetermined directions.

8. The shot diverter of claim 1 wherein said ridge means are most pronounced at the exit end and become proportionately less pronounced per unit of length towards the entry end, thereby gradually sloping downwardly from the exit to the entry end so as to merge into the surface of said wall means proximate the entry end, and thereby providing for gradual but positive alignment of selective shot pellets into predetermined directions.

9. The diverter of claim 1 wherein said elongate tubular body further includes, adjacent the entry end thereof, means for suppressing fiash and noise upon firing of the gun.

10. The diverter of claim 1 wherein said means for suppressing noise includes a plurality of apertures defined by longitudinal and lateral walls, the intersection of said longitudinal and lateral walls being characterized by fillet means for creating areas of turbulent gas flow, thereby reducing the pitch of audio waves omitted through said apertures.

11. The diverter of claim 1 wherein said lateral walls extend around a major portion of the perimeter of said tubular body and are substantially equidistant from each other and,

each of said longitudinal walls are of substantially the same length as said lateral walls to thereby provide a plurality of equidistantly spaced apertures which exposes a major portion of the tube interior to the atmosphere so as to permit the total reflection of soft gases back over the apertures in covering relation thereto as a shell wad passes down the tubular body, thereby elevating the pressure of hard gases in the tube in order to enhance ignition in the bore and thus eliminating visible flash.

References Cited UNITED STATES PATENTS 587,801 8/ 1897 DurnfOrd 42-79 1,636,357 7/1927 Cutts t. 89-14 1,773,260 8/1930 Cutts 42--79 2,658,298 11/ 1953 Oberfell 42-79 3,226,871 1/ 1966 Sargeant et al. 42-79 2,602,255 7/ 1952 Cutts 42-79 SAMUAL W. ENGLE, Primary Examiner U.S. Cl. X.R. 89--14

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