Title:
Firearms projectile having jacket runner
Kind Code:
A1


Abstract:
A projectile for small munitions is provided having a bullet with an integral jacket runner formed from a resilient, shape-retaining material. The projectile comprises a bullet having a tapered front section, a cylindrical middle section and a tapered end section. The middle section includes a recessed retaining portion over which the resilient jacket runner is securely positioned or formed. The maximum diameter of the bullet is less than the primary bore diameter of the firearm barrel, and the outer diameter of the jacket runner when positioned around the bullet, is slightly greater than the primary bore diameter, whereby rifling in the barrel scores the jacket runner and not the bullet, and imparts spin to the jacket runner during firing and hence to the bullet which is integral therewith, achieving enhanced gas checking efficiency, accuracy and velocity. The integral jacket runner remains on the bullet after firing and downrange to its ultimate destination. High speed production of this projectile can be achieved due to the resiliency or elastic memory of the jacket runner.



Inventors:
Hober, William D. (Easton, CT, US)
Application Number:
11/055387
Publication Date:
02/09/2006
Filing Date:
02/10/2005
Assignee:
Hober Holding Company
Primary Class:
International Classes:
F42B10/00
View Patent Images:



Primary Examiner:
PARSLEY, DAVID J
Attorney, Agent or Firm:
Hovey Williams LLP (Overland Park, KS, US)
Claims:
I claim:

1. A small munitions projectile for a firearm having a barrel with a primary bore of a certain diameter, the projectile comprising: a bullet having a longitudinal axis and a maximum diameter, the bullet comprising a tapered front section, a cylindrical middle section having a certain diameter and an axial length, and an end section, the middle section having opposed top and bottom portions and a cylindrical recessed receiving portion intermediate the top and bottom portions, the recessed receiving portion having a diameter less than the middle section diameter, and an elongated ring-shaped jacket runner formed from a resilient, shape-retaining material, the jacket runner securely positioned co-axially around the bullet adjacent the recessed receiving portion, the jacket runner having an inner diameter slightly less than or equal to the recessed receiving portion diameter, and an outer diameter greater than the diameter of the middle section, and wherein the maximum diameter of the bullet is less than the primary bore diameter of the firearm, and the outer diameter of the jacket runner is greater than the primary bore diameter of the firearm.

2. The projectile as set forth in claim 1, wherein the recessed receiving portion has a leading edge and a trailing edge, further comprising a first shoulder connecting the leading edge to the top portion of the middle section, and a second shoulder connecting the trailing edge to the bottom portion of the middle section.

3. The projectile as set forth in claim 2, wherein the first and second shoulders extend at an angle of from about 80° to about 100° with respect to the longitudinal axis of the bullet.

4. The projectile as set forth in claim 1, wherein the recessed receiving portion extends along approximately 50-95% of the axial length of the middle section of the bullet.

5. The projectile as set forth in claim 1, wherein the jacket runner extends along approximately 50-95% of the axial length of the middle section of the bullet.

6. The projectile as set forth in claim 1, wherein the jacket runner comprises a single piece.

7. The projectile as set forth in claim 1, wherein the jacket runner material has an elastic memory.

8. The projectile as set forth in claim 7, wherein the jacket runner material is a synthetic material.

9. The projectile as set forth in claim 8, wherein the material comprises polyethylene.

10. The projectile as set forth in claim 1, wherein the end section is tapered.

11. The projectile as set forth in claim 1, wherein the end section includes a rear surface.

12. The projectile as set forth in claim 1 1, wherein the rear surface is essentially flat.

13. The projectile as set forth in claim 11, wherein the rear surface is essentially conical in cross-section.

14. The projectile as set forth in claim 1, wherein the tapered front section further includes a tip secured thereon.

15. The projectile as set forth in claim 1, wherein the jacket runner is adapted to remain on the bullet subsequent to firing of the firearm and on downrange to its final destination.

16. A process for making a small munitions projectile including a bullet having a longitudinal axis, a front section, a middle section having an axial length and including a top portion and a bottom portion, and an end section, the bullet including a maximum diameter, and a jacket runner positioned therearound intermediate the top portion and the bottom portion, said process comprising: forming a bullet having a cylindrical recessed receiving portion intermediate the top portion and bottom portion of the middle section, the recessed receiving portion having a diameter less than the maximum diameter of the bullet; forming an elongated ring-shaped jacket runner from a resilient, shape-retaining material, the jacket having an outer diameter, and an inner diameter less than or equal to the diameter of the recessed receiving portion; stretching the jacket runner for passing over the maximum diameter of the bullet; positioning the jacket runner over the recessed receiving portion; allowing the jacket runner to return essentially to its original size and shape, wherein the outer diameter of the jacket runner is greater than the maximum diameter of the bullet; and securing the jacket runner onto the recessed receiving portion, wherein the jacket runner is adapted to remain integral with the bullet even subsequent to firing it from a firearm.

17. The process as set forth in claim 16, wherein forming the bullet includes forming the recessed receiving portion with a leading edge and a trailing edge, said bullet forming step further comprising forming a first shoulder connecting the leading edge to the top portion of the middle section, and forming a second shoulder connecting the trailing edge to the bottom portion of the middle section.

18. The process as set forth in claim 17, further comprising forming the first and second shoulders each at an angle of from about 80° to about 100° with respect to the longitudinal axis of the bullet.

19. The process as set forth in claim 16, wherein the recessed receiving portion is formed to extend along approximately 50 to about 95% of the axial length of the middle section of the bullet.

20. The process as set forth in claim 16, wherein the jacket runner is formed to extend along approximately 50 to about 95% of the axial length of the middle section of the bullet.

21. A process for making a small munitions projectile including a bullet having a longitudinal axis, a front section, a middle section including a top portion and a bottom portion, and an end section, the bullet including a maximum diameter, and a jacket runner positioned therearound, said process comprising: forming a bullet having a cylindrical recessed receiving portion intermediate the top portion and bottom portion of the middle section, the recessed receiving portion having a diameter less than the maximum diameter of the bullet; forming an elongated ring-shaped jacket runner around the recessed receiving portion, the jacket runner formed from a resilient, shape-retaining synthetic material, and having an outer diameter, and an inner diameter less than or equal to the diameter of the recessed receiving portion; and securing the jacket runner onto the recessed receiving portion, wherein the jacket runner is adapted to remain integral with the bullet even subsequent to firing it from a firearm.

22. The process as set forth in claim 21, wherein the recessed receiving portion includes a leading edge and a trailing edge, said bullet forming step further comprising forming a first shoulder connecting the leading edge to the top portion of the middle section, and forming a second shoulder connecting the trailing edge to the bottom portion of the middle section.

23. The process as set forth in claim 22, further comprising forming the first and second shoulders each at an angle of from about 80° to about 100° with respect to the longitudinal axis of the projectile.

24. The process as set forth in claim 21, wherein the recessed receiving portion is formed to extend along approximately 50 to about 95% of the axial length of the middle section of the bullet.

25. The process as set forth in claim 21, wherein the jacket runner is formed to extend along approximately 50 to about 95% of the axial length of the middle section of the bullet.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of the provisional application entitled FIREARMS PROJECTILE HAVING DRIVING BAND, Ser. No. 60/543,437, filed Feb. 10, 2004. This application is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates in general to small firearms projectiles, and, more particularly, small munitions projectiles having bullets with integral jacket runners.

2. Description of the Related Art

Conventional muzzle loader bullets began with the use of a lead ball projectile, utilizing a wet cloth patch to provide the gas checking element within the barrel. This evolved into conical shaped projectile designs made of various metal configurations, utilizing wrapper or sabot devices surrounding the bullet to provide gas checking. These various sabot designs engage the bore in the depth of the lands, allowing undersized bullets to be used within the sabot cavity, wherein these undersized bullets have no or limited contact with the riflings or bore of the firearm barrel.

Conventional projectiles utilizing sabot configurations typically have included two distinct parts, the first being the bullet, and the second being the sabot which was designed to separate from the bullet subsequent to firing. As the first sabots completely surrounded the bullet and thus were located between the bullet and the bore/lands, it was believed that they disadvantageously interfered with the accuracy of the fired bullet. In addition, sabots were designed to detach from the bullet immediately upon firing and can cause bullet deflection and thereby impede the velocity and accuracy of the fired bullet.

As the bullets and associated sabots were improved, sabots such as that disclosed in U.S. Pat. Nos. 5,458,064 and 5,621,187, both issued to Robert Kearns, were used. This abbreviated sabot was essentially a gas check device attached to, and extending from, the base of the bullet. Again, the gas check device was designed for use with an undersized bullet, the device having a diameter greater than the bore diameter. In this manner, the gas check device contacted the riflings or bore of the barrel, while the metal projectile disclosed had limited contact with the bore and lands of the firearm barrel. Again, it was emphasized in those patents that the gas check device was designed to detach from the bullet upon firing of the firearm.

When the sabots of these prior projectiles detach from the bullet subsequent to firing, they actually cause deflection of the bullet and negatively affect the downrange accuracy, and rotational stability of the projectile can be compromised. Accordingly, there is a need for a projectile incorporating a device which is integral with the bullet, thereby remaining on the bullet subsequent to firing and in flight as the bullet arrives at its target. Further, there is a need for a projectile incorporating a jacket runner which is formed as one piece from a resilient, shape-retaining material, so that it can be securely retained around the bullet, and also can be manufactured in a high speed, cost effective process.

BRIEF SUMMARY OF THE INVENTION

Accordingly, the small munitions firearm projectile of the present invention comprises a bullet having a longitudinal axis and a maximum diameter, the bullet comprising a tapered front section, a cylindrical middle section having a certain diameter, and an end section. The middle section has opposed top and bottom portions, and a cylindrical recessed receiving portion intermediate the top and bottom portions, the recessed receiving portion having a diameter less than the middle section diameter. The projectile further comprises an integral elongated ring-shaped jacket runner formed from a resilient, shape-retaining material, the jacket runner securely positioned co-axially around the bullet adjacent the recessed receiving portion. The jacket runner has an inner diameter slightly less than or equal to the recessed receiving portion diameter, and an outer diameter slightly greater than or equal to the diameter of the middle section when the jacket runner is positioned thereon. The maximum diameter of the bullet is less than the primary bore diameter of the firearm barrel, and the outer diameter of the jacket runner is greater than the primary bore diameter.

In another embodiment, the recessed receiving portion has a leading edge and a trailing edge, with a first shoulder formed to connect the leading edge to the top portion of the middle section, and a second shoulder formed to connect the trailing edge to the bottom portion of the middle section. It is contemplated that the first and second shoulders each extend at angle of from about 800 to about 1000 with respect to the longitudinal axis of the bullet for retaining the jacket runner on the bullet after firing.

In addition, a method of making a small munitions firearms projectile comprising a bullet having an integral jacket runner is provided. This method includes providing a bullet having a longitudinal axis, a front section, a cylindrical middle or shank section including a top portion and a bottom portion, and an end section, and further having a maximum diameter; providing a recessed cylindrical receiving portion intermediate the top portion and bottom portion of the middle section and having a diameter less than that of the remaining portions of the middle section; providing an elongated, ring-shaped jacket runner formed from a resilient, shape-retaining material, the jacket having an outer diameter, and an inner diameter slightly less than or equal to the diameter of the recessed receiving portion diameter; stretching the jacket runner for passing over the maximum diameter of the bullet; positioning the jacket runner over the recessed receiving portion; allowing the jacket runner to return substantially to its original size and shape, wherein the outer diameter of the jacket runner is greater than the maximum diameter of the bullet; and securing the jacket runner onto the recessed receiving portion, wherein the jacket runner is adapted to remain integral with the bullet even subsequent to firing it from a firearm.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 is a perspective view of a projectile in accordance with the present invention.

FIG. 2 is an exploded view of the projectile of FIG. 1.

FIG. 3 is an enlarged side sectional view of the projectile of FIG. 3.

FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 3.

FIG. 5. is an enlarged fragmentary cross-sectional view of the projectile of the present invention positioned within the barrel of a firearm having rifling.

FIG. 6 is a fragmentary side view of a projectile in accordance with the present invention, positioned within a centerfire or rimfire rifle cartridge.

FIG. 7 is a fragmentary side view of a projectile in accordance with the present invention, positioned within a centerfire or rimfire handgun cartridge.

FIG. 8 is a fragmentary side view of a projectile in accordance with the present invention, positioned within a shotgun hull.

DETAILED DESCRIPTION OF THE INVENTION

Turning now to the FIGS., and particularly to FIGS. 1-3, a projectile 10 for small munitions is depicted, and includes a bullet 12 and an integral jacket runner 14. Optionally, the projectile can also include a tip 16 positioned on one end thereof.

Bullet 12 includes a tapered front section 20, a cylindrical middle section or shank 22, and a tapered end section 24. Section 20 includes opposed top 46 and bottom 48 ends, and intermediate these opposed ends is a recessed receiving portion 26 for receiving and retaining jacket runner 14 thereon. Both middle section 22 and recessed receiving portion 26 are preferably circular in cross-section. Recessed receiving portion 26 has opposed leading and trailing edges 28 and 30; respectively. Leading edge 28 is connected to top end 46 by first shoulder 32, and trailing edge 30 is connected to bottom end 48 by second shoulder 34. Shoulders 32, 34 can form any suitable size and angle with respect to the outer diameter and longitudinal axis of bullet 12, and can function to limit the forward and rearward movement of jacket runner 14, as will be discussed in more detail below.

The opposed ends of bullet 12 include front surface 36 and rear surface 38. Front surface 36 can optionally include tip 16 extending therefrom. Tip 16 can be secured to front surface 36 of bullet 12 by any suitable means. In one embodiment, the means of attachment includes a recess or inlet 40 extending inwardly therefrom, and adapted to receive therein receiving end portion 42 of tip 16. Receiving end 42 can be secured within inlet 40 by means of swaging, or the like. Alternatively, adhesive or other suitable securing means can be utilized. Any suitable shape and size of tip can be utilized, and is contemplated to be within the scope of the present invention. Rear surface 38 can be flat or conical, or any suitable shape. In the embodiment depicted in FIG. 1, rear surface 38 is flat, and in FIG. 8, rear surface 338 is conical. Again, any suitable configuration of the rear surface, including a flat surface, a conical surface, or any other geometric configuration, is contemplated to be within the scope of the invention.

Bullet 12 can be formed from any suitable material known in the industry. These materials can include metals such as copper, lead or any suitable hard metal, as well as known thermoplastic materials.

Jacket runner 14 is an elongated ring-shaped band, as is best seen in FIG. 2, and fits co-axially around recessed receiving portion 26. Typically, jacket runner 14 is formed from a resilient, shape-retaining material and has an inner diameter which is slightly less than the outer diameter of recessed receiving portion 26. In this manner, runner 14 can be secured thereon by means of a compression or tension fit, or a friction fit. Alternatively, any other suitable securing means can be utilized, including adhesives or the like, or by means of an injection molding process by which jacket runner 14 is formed directly onto bullet 12. As discussed above, jacket runner 14 is securely positioned on recessed receiving portion 26 and thereby forms an integral part of bullet 12. In a preferred embodiment, jacket runner 14 extends along essentially the entire axial length of recessed receiving portion 26. For example, if the axial length of recessed receiving portion is 0.480″, the axial length of jacket runner 14 is about 0.470″. Similarly, if the axial length of recessed receiving portion 22 is 0.350″, the axial length of jacket runner 14 is about 0.340″. It is understood that these figures are provided for purposes of illustration only, as they will vary according to the grain weight or length of the specific bullet. Further, the axial length of recessed receiving portion 26 and corresponding jacket runner 14 in a preferred embodiment extend along a large portion of the axial length of the middle section or shank 22 of bullet 12, and preferably extends along about 50 to 95% ofthe axial length ofthe middle section 22 thereof. This elongated runner 14 increases gas checking efficiency, improving velocity and accuracy of the fired projectile.

As best seen in FIG. 3, recessed receiving portion 26 is of sufficient depth and runner 14 is of sufficient thickness so that the outer diameter of jacket runner 14, when positioned around bullet 12, is slightly greater than the maximum diameter of bullet 12, which maximum diameter is typically that of the outer diameter of middle section 22. By varying the outer diameter of jacket runner 14, the pressures and velocity of the fired projectile 10 can be varied, as explained below. The thickness of jacket runner 14 will vary according to the depth of recessed receiving portion 26, and to the caliber and bore dimensions of the firearm, and should be sufficient to provide effective gas checking and rotational stability as the bullet travels through the barrel. It is important that the inner diameter, thickness, strength and elasticity of jacket runner 14 are sufficient to allow runner 14 to stretch over the largest diameter of the projectile, typically middle section 22, without tearing, and to thereafter allow jacket runner 14 to return to its original diameter and be retained securely on bullet 12 within recessed receiving portion 26. The thickness must also be sufficient to prevent runner 14 from rolling up and over the first shoulder 32 or second shoulder 34 during loading or firing of the projectile 10, or while the projectile is traveling to its down range destination. This thickness also provides strength and critical mass, preventing air from getting under jacket runner 14 during flight of the projectile 10, which could cause it to yaw or otherwise affect the accuracy thereof. As an example, if the recessed portion of a 50 caliber muzzle loader bullet is 0.019″ deep, jacket runner 14 can be approximately 0.023″ thick when positioned around the bullet 12. With this specific size, jacket runner 14 will extend approximately 0.004″ from the outer surface of the maximum diameter of middle section 22. Likewise, if the recessed portion 26 is 0.0514″ deep, the jacket runner 14 can be approximately 0.0585″ thick when positioned around recessed receiving portion 26, extending approximately 0.007″ from the outer surface of the maximum diameter of middle section 22.

Jacket runner 14 is positioned intermediate leading edge 28 and trailing edge 30. First shoulder 32 limits the forward movement of jacket runner 14, while second shoulder 34 limits the rearward movement thereof. The angle of shoulders 32, 34 with respect to the longitudinal axis of bullet 12 is thus preferably sufficient to limit the forward and rearward movement of jacket runner 14 to ensure that it is retained on the bullet 12 after firing from a firearm. In a preferred embodiment, this angle is approximately 90°, although suitable angles ranging from approximately 80° to 100° are also within the scope of this invention.

Jacket runner 14 can be constructed from any suitable material, although it is preferably formed from a synthetic material which has a number of important characteristics. This synthetic material should be resilient and pliable, such as a deformable polymer, plastic or the like, and must be strong enough to withstand the high pressures created during discharge of the firearm without rupturing. In addition, the material from which jacket runner 14 is formed should have an elastic memory, i.e., the material can be temporarily deformed, and then can substantially recover its original shape and size after the deforming force has been removed. Suitable materials also include those which are sufficiently heat resistant and able to withstand the high flash temperatures created during ignition or burning of the propellant during discharge of the firearm, without melting, burning, or otherwise deforming. Each of these characteristics will be dealt with in more detail below.

First, the synthetic material should be sufficiently malleable or pliable to temporarily deform under the pressure created during firing of the projectile, so that the runner 14 spreads out and fills at least a portion of the depth of the lands 52 in the rifle, thereby capturing and delivering the maximum possible propellant energy and ensuring efficient gas checking, and also enhancing the rotational stability of projectile 10 as it travels down the barrel. This malleability is further relevant in the loading of the projectile 10 in a muzzle loader application, as it allows projectile 10 to be loaded straight within the center of the rifle bore, and also allows it to travel down the barrel essentially centered in the bore thereof.

Second, the material of runner 14 must have a strength sufficient to withstand the pressures generated from the ignition of the powder charge, and to fill the lands 52 with a proper gas check. These pressures can, for example, exceed approximately 30,000 psi in a muzzle loader application, and approximately 65,000 psi in a center fire rifle application. Its strength must further be sufficient to keep the bullet 12 essentially centered within the bore of the firearm as it travels down and departs the barrel. Further, the runner material must be able to endure the rotational projectile snap when fired, with the generation of over 200,000 rpm. The integrity of the runner's strength cannot permit it to depart from the bullet 12, nor can it fray, tear or fragment into pieces when initially fired, or when traveling down range to its ultimate destination. The strength of synthetic jacket runner 14 can be measured in terms of tensile strength at yield, which is the pulling stress, in psi, required to break a given specimen. Tensile strength represents the resistance of runner 14 to tearing, even in conjunction with the flash temperatures to which the projectile is exposed during discharge of the firearm. Another measurement of the strength or toughness of the material is the Izod impact test, which is designed to determine the resistance of a plastics material to a shock loading. This test involves the notching of a specimen, which is then placed in the jaws of a machine and struck with a weighted pendulum. Sufficient strength is required in the selected material to impart to runner 14 the ability to remain with bullet 12 subsequent to firing, without rupturing or tearing.

Third, the material selected for jacket runner 14 must have an elastic memory. Specifically, the elastic memory must be sufficient to return runner 14 substantially to its original dimension subsequent to the stretching thereof over the greatest diameter of bullet 12, and the ultimate positioning thereof onto recessed receiving portion 26, if required during one of the possible manufacturing processes. The tension or elasticity of this material allows for high speed manufacturing of small caliber and sizes of bullets in accordance with the present invention, which high speed could not be achieved using metal, porcelain or other non-elastic materials for runner 14, nor using items manufactured from multiple pieces which would require alignment and installation around the bullet. In addition, the elasticity of the material must also cause jacket runner 14 to be retained in place on bullet 12 after firing as the projectile travels through the barrel and down range to its ultimate destination. As discussed above, the inner diameter of runner 14 is slightly less than the outer diameter of recessed receiving portion 26, providing one means of securing runner 14 onto bullet 12, namely compression or friction fit, although other means of securing runner 14 onto bullet 12 are contemplated. This fit between runner 14 and recessed receiving portion 26 must be sufficiently tight to retain runner 14 in place and eliminate any air from getting between runner 14 and bullet 12 during flight, which would negatively affect accuracy of the projectile 10, as by yawing or the like. One measurement of the elasticity or memory of the material is its elongation at yield, which is the limit to which the material can be stretched and still return to its original shape. Another measurement of this property is the flexural strength of the material, which relates not only to its memory, but also to its strength. This measurement determines the degree to which the material can be bent before its outermost fibers fail, and the material thereby takes on a different dimension.

Next, the synthetic material selected for jacket runner 14 must be able to withstand flash temperatures of up to approximately 1500° Fahrenheit without burning, melting or disintegrating. The runner 14 is exposed to this flash temperature for only a fraction of a second during firing of the firearm. It is understood that this resistance to heat is a measure of temperature given a specific parameter of time. Thus, materials which would melt if exposed to this temperature for any extended period of time can still be suitable for the runner 14 of this invention. One measurement of the heat resistance of a material is its deflection temperature, which is the temperature to which a material can be exposed before it changes form or in some way becomes distorted. If the deflection temperature is too low, jacket runner 14 could possibly melt during the discharge of the firearm.

In addition, a preferred synthetic material selected for jacket runner 14 should have a coefficient of friction which satisfies the needs of a given projectile application. In a muzzle loader application, where the bullet is loaded from the muzzle end of the rifle and put into place in the chamber of the barrel, an increase in the coefficient of friction makes the projectile 10 more difficult to load, but will result in higher pressures being formed subsequent to firing, with projectile 10 thereby achieving higher velocities. Conversely, a lower coefficient of friction of the jacket runner material will make the projectile 10 easier to load, but will result in the creation of lower pressures during firing, and thus slower velocities of the projectile. As a result, by varying the coefficient of friction of the material of jacket runner 14, the pressure and resultant velocity of the projectile 10 can be controlled, allowing for finite adjustments of the projectile performance. In one embodiment, the coefficient of friction of the material can be varied by incorporating a slip agent into the synthetic material used to form runner 14.

Any material suitable for use in the formation of jacket runner 14 preferably employs most or all of the characteristics discussed above. Typically, synthetic materials or plastics are the most useful in accordance with the teachings of the present invention. These can include any of a number of thermoplastic resins, or combinations thereof, such as, without limitation, cellulose acetate, nylon, polyester, low density polyethylene, high density polyethylene, silicone, acetal, acrylonitrile butadiene styrene, homopolymer polypropylene, copolymer polypropylene, polycarbonate, and linear low density polyethylene. Additives can be employed in combination with these materials as extenders or modifiers, depending on the characteristics desired for any given application. One example of such an additive is a slip agent which can be used to modify the coefficient of friction of the runner material by adding lubricity to the surface of the material. Fillers can also be employed to improve physical properties, particularly hardness, stiffness, and impact strength.

In one example in accordance with the present invention,jacket runner 14 is formed from a thermoplastic material such as high density polyethylene. When manufactured by an injection molding process, the melt index of the material becomes important, and is measured as the amount, in grams, of a thermoplastic resin which can be forced through a 0.0825 inch orifice when subjected to 2160 gms. force in 10 minutes at 190° C. In this example, the high density polyethylene forming the jacket runner 14 can have a flow rate of about 7 to 10 g/10 min., and a preferred flow rate is about 8 g/10 min. The specific gravity of such a resin is the density, or weight per unit volume, of the material divided by that of water at a standard temperature, usually 4° C. Since water's density is nearly 1.0 g/cc, density described in terms of g/cc and specific gravity are numerically equal. In the present example, the density of this polyethylene can range from about 0.953 to 0.960 g/cc., with 0.954 g/cc being a preferred specific density. As discussed above, the strength of the runner material in accordance with the present invention is important for retaining jacket runner 14 on bullet 12 during firing and down range to the target. The tensile strength of the jacket runner material can, for example, be in the range of about 3300 to 4800 psi, and in one embodiment is preferably about 4000 psi. According to the measurements achieved by the Izod impact test, the strength of the high density polyethylene of the present example can range from about 1.1 to 1.4 ft-lb/in., and is preferably about 1.4 ft-lb/in. The elasticity of this particular material, expressed as elongation at yield, is between about 750 and 950%, with the preferred elongation being about 800%. Further, this high density polyethylene can have a flexural module of about 1.2 to 2.4×10E5 psi, and is preferably about 1.4×10E5 psi. Finally, the deflection temperature of the synthetic material of runner 14 can be about 160 to 170° F. @ 66 psi, and is preferably about 160°0 F. @ 66 psi. While this deflection temperature may seem low in relation to the flash temperatures of up to 1500° F. reached during discharge, it is sufficient, as the runner 14 is only exposed to this flash temperature for a fraction of a second.

Of course, it is understood that these values and properties listed above represent only one specific example of a high density polyethylene material which is useful for forming the jacket runner 14 of the present invention, and is not intended to limit in any manner the materials which are within the scope of the present invention. Other suitable materials which can be useful in accordance with the present invention, and indeed which are contemplated as being within the scope of this invention, can exhibit a wide variety of different property values, so long as the material provides a jacket runner which is capable, among other characteristics, of remaining on the bullet 12 after firing and down range to its ultimate target. Thus, for example, if the specific elastic memory and the strength of an otherwise suitable material is not within any of the given value ranges set forth above with respect to the polyethylene, such material may, given its specific combination of characteristics values, provide a suitable jacket runner material which is contemplated to be in accordance with the present invention.

During manufacture of the jacket runner 14 of the present invention, when a resilient plastic or polymer is utilized, in one embodiment the jacket runner 14 is formed by extrusion or by injection molding, or the like, depending upon the specific material selected for runner 14, or its specific application. Extrusion is the compacting of a plastics material and the forcing of it through an orifice in a more or less continuous fashion. Injection molding involves softening a thermoplastic material by heating the same, and then forcing the softened material from a plasticizing device into a relatively cool mold cavity for hardening. Once formed, jacket runner 14 is temporarily stretched to fit over the maximum diameter of bullet 12, and is then positioned over recessed receiving portion 26. Subsequent to such positioning, jacket runner 14 returns substantially to its original size and becomes integral with middle section 22 by means of a tension or compression fit. Alternatively, jacket runner 14 can be formed directly around recessed receiving portion 26 by injection molding or the like, or can be secured thereon by any suitable securing means. As discussed above, it is preferable for the outer diameter of jacket runner 14 to be slightly larger than the maximum outer diameter of bullet 12, and particularly of middle section 22 thereof. Upon firing, the explosive forces cause the trailing end of jacket runner 14 to temporarily expand or otherwise deform to some degree within the bore, creating enhanced gas checking efficiency and rotational stability as explained below.

The barrels of firearms can have smooth or rifled bores extending therethrough. The bore has a diameter which is the distance between opposed inner surfaces of the barrel when the barrel is smooth, i.e., not rifled, and it is the distance between opposed land surfaces when the barrel is rifled. In rifled bores, lands 52 are raised portions which extend inwardly from the outer bore 54, creating an inner or primary bore 56. As best seen in FIG. 5, jacket runner 14 positioned around bullet 12 has an outer diameter greater than the diameter of primary bore 56, whereby lands 52 are designed to cut into or form rifling patterns in jacket runner 14 as the projectile 10 is fired from the firearm. The rifling or lands 52 impart spin to jacket runner 14, and thus to bullet 12 which is integral therewith. In smooth bores and with the absence of riflings, a critical dimension of the projectile 10 becomes the relative size of the jacket runner 14 with respect to the diameter of the barrel. In both smooth and rifled bores, jacket runner 14 functions to hold projectile 10 in place and prevent bullet 12 from contacting the bore or limit its contact therewith, eliminating fouling caused by scoring of the metal. In addition, jacket runner 14, as it expands within the bore from the pressure of the firing explosion, performs a gas checking function, i.e., it works to prevent or limit the escape of gases generated during firing. Thus, by increasing or decreasing the outer diameter of runner 14, pressures and velocities can be controlled. Although the dimensions and variations of performance will change with respect to projectiles for different applications, namely, muzzle loader, shotgun slug, revolver or handgun, and rifle, the principles and advantages achieved by the bullet and jacket runner of the present invention will be essentially the same. For example, in a 50 caliber muzzle loader application, for each one thousandths of an inch increase or decrease in this outer diameter, as from 0.501 to 0.507, the muzzle velocity will change about 200 feet per second. Further, in such a muzzle loader firearm, ease of loading will be dramatically affected by the finished outer diameter of jacket runner 14 when installed within recessed receiving portion 26 of bullet 12.

As one example of a projectile in accordance with the teachings of the present invention, when a 50 caliber muzzle loader bullet having a weight of 250 grains is used, bullet 12 will be undersized, and preferably will have a maximum diameter of approximately 0.498″ at middle section 22, with recessed receiving portion 26 having a diameter of approximately 0.469″. Jacket runner 14 positioned around recessed receiving portion 26 will have an outer diameter of about 0.504″ to about 0.506″. Thus, in the rifled bore depicted in FIG. 5, the primary bore is approximately 0.500, and the secondary bore is about 0.510. The outer surface of jacket runner 14 will be scored by lands 52 after firing, thus retaining bullet 12 centered within barrel 20. In this way, contact between bullet 12 and bore 56 is minimized or eliminated, and therefore no or limited scoring or other deformation of bullet 12 occurs during the loading and firing processes. As pressure builds up within the bore during firing, the malleability or suppleness of jacket runner 14 causes it to deform to some degree and fill in the depths of lands 52 to the secondary bore dimension of the rifle barrel. This ensures proper gas checking and rotational stability of projectile 10 as it travels down the barrel and to its final destination.

In manufacturing the projectile of the present invention, the bullet 12 is first formed by conventional means, such as by casting or impact heading or the like, and middle section 22 of the bullet is provided with recessed receiving portion 26. As discussed above, in one embodiment, jacket runner 14 is formed by any suitable process such as injection molding, extrusion or the like. It is then deformed or stretched and positioned over bullet 12 adjacent recessed receiving portion 26, after which jacket runner 14 is allowed to return essentially to its original size or form. As the inner diameter of jacket runner 14 in its original size is slightly less than the outer diameter of recessed receiving portion 26, runner 14 is retained securely around bullet 12 by means of a tension or compression fit, a friction fit, or other suitable securing means. In an alternative embodiment, jacket runner 12 is formed in place around recessed receiving portion 26 by injection molding or the like. The tension or elasticity of this material allows for high speed, cost effective manufacturing of small caliber and sizes of bullets in accordance with the present invention, which high speed could not be achieved using metal, porcelain or other non-elastic materials for runner 14, nor using items manufactured from multiple pieces which would require alignment and installation around the bullet.

Although much of this discussion has been directed to projectiles for muzzle loader firearms, the teachings of the present invention are equally useful for projectiles used for a variety of applications, including slugs for shot guns, centerfire or rimfire rifle bullets, and centerfire or rimfire handgun bullets. Some of these projectiles are depicted in FIGS. 6-8.

Turning now to FIG. 6, a projectile 110 is depicted which includes a bullet 112, a jacket runner 114, and a cartridge 115, and is of the configuration typically associated with centerfire or rimfire rifles. Optionally, the projectile can also include a tip 116 positioned on one end thereof. Bullet 112 includes a tapered front section 120, a cylindrical middle section 122, and a tapered end section 124. Intermediate the opposed end portions of middle section 122 is a recessed receiving portion 126 for receiving jacket runner 114 thereon. Both middle section 122 and recessed receiving portion 126 are preferably circular in cross-section. Recessed receiving portion 126 has opposed leading edge (not shown) and trailing edge 130. The leading edge is connected to middle section 122 adjacent one opposed end portion thereof by a first shoulder (not shown), and trailing edge 130 is connected to middle section 122 adjacent the second opposed end portion thereof by second shoulder 134. The shoulders can form any suitable angle with respect to the longitudinal axis of bullet 112, and function to limit the forward and rearward movement of jacket runner 114 after firing and during flight, in the same manner as discussed above with respect to FIGS. 1-3. The front end of bullet 112 can optionally include tip 116 extending therefrom. Tip 116 can be secured to the front surface of bullet 112 by any suitable means of attachment, including the recess and swaging configuration as shown in FIGS. 2-3 above, or suitable adhesives or the like.

When used with centerfire or rimfire rifles, bullet 112 is positioned partially within centerfire cartridge 115 adjacent end section 124. Centerfire cartridge 115 can be of any suitable configuration, and in the embodiment of FIG. 6, encompasses end section 124 and extends partially over middle section 122 and jacket runner 114. As in conventional applications, cartridge 115 is filled with charge 150, and upon firing, projectile 110 detaches from cartridge 115 and travels through and exits firearm barrel toward its target.

As discussed above, jacket runner 114 is an elongated ring-shaped band which fits co-axially around recessed receiving portion 126. Typically, jacket runner 114 is formed from a resilient, shape-retaining material and has an inner diameter which is slightly less than the diameter of recessed receiving portion 126. Accordingly, it can be secured thereon by means of a tension or compression fit, or a friction fit. Alternatively, any other suitable securing means can be utilized for securing jacket runner 114 to bullet 112, including adhesives or the like, or by forming jacket runner 114 directly around bullet 112 by injection molding or the like. Jacket runner 114 is securely positioned around recessed receiving portion 126 intermediate the leading edge and trailing edge 130, and thereby forms an integral part of bullet 112. In a preferred embodiment, jacket runner 114 extends along essentially the entire axial length of recessed receiving portion 126. Further, it is preferred that the recessed receiving portion 126 and corresponding jacket runner 114 extend along a major portion of the axial length of the middle section or shank 122 of bullet 112, and preferably from 50 to 95% of the axial length thereof. This elongated configuration helps to achieve increased gas checking efficiency and rotational stability. Recessed receiving portion 126 is of sufficient depth such that the outer diameter of jacket runner 114 is slightly greater than the maximum diameter of bullet 112 when runner 114 is positioned thereon.

Jacket runner 114 is constructed from any suitable materials, as discussed above with respect to jacket runner 14, and preferably includes the same characteristics of pliability, strength, elastic memory, resistance to heat, and coefficient of friction. When a resilient plastic is utilized as the runner material, in one embodiment jacket runner 114 is temporarily stretched during manufacture of the projectile 110 to fit over the maximum diameter of bullet 112, and is positioned over recessed receiving portion 126, whereafter it returns to substantially its original size and becomes integral with middle section 122, secured thereto by means of a tension or compression fit. In an alternative embodiment, jacket runner 114 is formed directly on bullet 112 by injection molding or the like, or can be secured thereon by any suitable securing means. Upon firing, the explosive forces cause the trailing end of elongated jacket runner 114 to temporarily expand or otherwise deform to some degree within the bore, creating enhanced gas checking efficiency and rotational stability.

Turning now to FIG. 7, a projectile 210 is depicted which includes a bullet 212, a jacket runner 214, and a cartridge 215, and is of a configuration typically associated with centerfire or rimfire handguns. Optionally, the projectile can also include a tip 216 positioned on one end thereof. Bullet 212 includes a tapered front section 220, a cylindrical middle section 222, and a tapered end section 224. Intermediate the opposed end portions of middle section 222 is a recessed receiving portion (not shown) similar to the recessed receiving portions 26, 126 of FIGS. 2 and 6, respectively, for receiving jacket runner 214 thereon. Both middle section 222 and recessed receiving portion are preferably circular in cross-section. Recessed receiving portion has opposed leading and trailing edges (not shown) connected to middle section 122 adjacent the corresponding opposed end portions thereof by a first shoulder and a second shoulder (not shown). The shoulders can form any suitable size and angle with respect to the diameter and longitudinal axis of bullet 212, and function to limit the forward and rearward movement of jacket runner 214, in the same manner as discussed above with respect to FIGS. 1-3. The front end of bullet 212 can optionally include tip 216 extending therefrom. Tip 216 can be secured to the front surface of bullet 212 by any suitable means of attachment, including the recess and swaging configuration as shown in FIGS. 2-3 above, or suitable adhesives or the like.

When used with centerfire or rimfire handguns, bullet 212 is positioned partially within cartridge 215 adjacent end section 224. Handgun cartridge 215 can be of any suitable configuration, and in the embodiment depicted in FIG. 7, encompasses end section 224 and extends partially over middle section 222 and jacket runner 214. As in conventional applications, cartridge 215 is filled with charge 250, and upon firing, projectile 210 detaches from cartridge 215 and travels through and exits from firearm barrel toward its target.

Jacket runner 214 is an elongated ring-shaped band which fits co-axially around the recessed receiving portion. In one embodiment, jacket runner 214 is formed from a resilient, shape-retaining material and has an inner diameter which is slightly less than the outer diameter of recessed receiving portion, so that it can be secured thereon by means of a tension or compression fit. Alternatively, any other suitable securing means can be utilized for securing jacket runner 214 to bullet 212, including adhesives or the like, or by forming jacket runner 214 directly around the recessed receiving portion by an injection molding process or the like. As discussed above, jacket runner 214 is securely positioned around recessed receiving portion intermediate the leading and trailing edges thereof, and thereby forms an integral part of bullet 212. In a preferred embodiment, jacket runner 214 extends along essentially the entire axial length of recessed receiving portion. Further, it is preferred that recessed receiving portion and corresponding jacket runner 214 extend along a major portion of the axial length of the middle section or shank 222 of bullet 212, and preferably from 50 to 95% of the axial length thereof. Recessed receiving portion is of sufficient depth such that the outer diameter of jacket runner 214 is slightly greater than the maximum diameter of bullet 212 when runner 214 is positioned thereon.

Jacket runner 214 is constructed from any suitable materials, such as those discussed above with respect to jacket runner 14, and preferably includes the same characteristics of pliability, strength, memory or elasticity, resistance to heat, and coefficient of friction. When a resilient plastic is utilized as the runner material, in one embodiment jacket runner 214 is temporarily stretched during manufacture of the projectile 210 to fit over the maximum diameter of bullet 212, and when positioned over the recessed receiving portion, it can return to substantially its original size and becomes integral with middle section 222, secured thereto by means of a tension or compression fit. Alternatively, jacket runner 214 can be formed directly around bullet 112 by injection molding or the like, or can be secured thereon by any suitable securing means. Further, upon firing, the explosive forces cause the trailing end of elongated jacket runner 214 to temporarily expand or otherwise deform to some degree, creating enhanced gas checking efficiency and rotational stability.

Turning now to FIG. 8, a projectile 310 is depicted which includes a bullet or slug 312, a jacket runner 314, and a cartridge or hull 315, and is of the configuration typically associated with shotgun slugs. Optionally, the projectile can also include a tip 316 positioned on one end thereof. Bullet 312 includes a tapered front section 320, a cylindrical middle section 322, and a tapered end section 324. Intermediate the opposed end portions of middle section 322 is a recessed receiving portion 326 for receiving jacket runner 314 thereon. Both middle section 322 and recessed receiving portion 326 are preferably circular in cross-section. Recessed receiving portion 326 has opposed leading edge (not shown) and trailing edge 330. The leading edge is connected to middle section 322 adjacent one opposed end portion thereof by a first shoulder (not shown), and trailing edge 330 is connected to middle section 322 adjacent the second opposed end portion thereof by a second shoulder 334. The shoulders can form any suitable angle with respect to the longitudinal axis of bullet 312, and function to limit the forward and rearward movement of jacket runner 314, in the same manner discussed above with respect to FIGS. 1-3.

The opposed ends of bullet 312 include a front surface 336 and a rear surface 338. Front surface 336 optionally includes tip 316 extending therefrom. Tip 316 can be secured to first section 320 of bullet 312 by any suitable means of attachment. In one embodiment, the means of attachment includes a recess or inlet 340 extending inwardly therefrom, and adapted to receive therein receiving end portion 342 of tip 316. Receiving end 342 can be secured within inlet 340 by means of swaging, or the like. Alternatively, adhesive or other suitable securing means can be utilized. Any suitable shape and size of tip can be utilized, and is contemplated to be within the scope of the present invention. Rear surface 338 can be flat or conical, or any suitable shape. In the embodiment depicted in FIG. 8, rear surface 338 is conical. Again, any suitable configuration of the rear surface is contemplated to be within the scope of the invention.

When used with shotguns, bullet 312 is positioned within shotgun hull 115 adjacent end section 324. Hull 315 can be of any suitable configuration, and in the embodiment of FIG. 8, essentially encompasses projectile 310. As in conventional applications, hull 315 is filled with charge 350, and upon firing, projectile 310 detaches from hull 315 and travels through and exits from firearm barrel toward its target.

Jacket runner 314 is an elongated ring-shaped band which fits co-axially around recessed receiving portion 326. In one embodiment, jacket runner 314 is formed from a material which is resilient and shape-retaining, and has an inner diameter which is slightly less than the diameter of recessed receiving portion 326, so that it can be secured thereon by means of a tension or compression fit. Alternatively, any other suitable securing means can be utilized for securing jacket runner 314 to bullet 312, including adhesives or the like, or by means of an injection molding process by which jacket runner 314 is formed directly around recessed receiving portion 326 of bullet 312. As discussed above,jacket runner 314 is securely positioned around recessed receiving portion 326 intermediate the leading edge and trailing edge 330 thereof, and thereby forms an integral part of bullet 312. In a preferred embodiment,jacket runner 314 extends along essentially the entire axial length of recessed receiving portion 326. Further, it is preferred that recessed receiving portion 326 and corresponding jacket runner 314 extend along a major portion of the axial length of the middle section or shank 322 of bullet 312, and preferably from 50 to 95% of the axial length thereof. Recessed receiving portion 326 is of sufficient depth such that the outer diameter of jacket runner 314 is slightly greater than the maximum diameter of bullet 312 when runner 314 is positioned thereon.

Jacket runner 314 is constructed from any suitable materials such as those discussed above with respect to jacket runner 14, and preferably includes the same characteristics of pliability, strength, elastic memory, resistance to heat, and coefficient of friction. When a resilient plastic is utilized as the runner material, in one embodiment jacket runner 314 is temporarily stretched during manufacture of the projectile 310 to fit over the maximum diameter of bullet 312, and is positioned ove recessed receiving portion 326, whereafter it returns substantially to its original size and becomes integral with middle section 322, secured thereto by means of a tension or compression fit. In an alternative embodiment, jacket runner 314 is formed directly around recessed receiving portion 26 by injection molding or the like, or can be secured thereon by any suitable securing means. Upon firing, the explosive forces cause the trailing end of jacket runner 314 to temporarily expand or otherwise deform to some degree, creating enhanced gas checking efficiency and rotational stability.

It can thus be seen that the combination bullet 12 and jacket runner 14 of the present invention provides a synergistic effect which results in a projectile 10 having enhanced velocity and accuracy characteristics. The metal bullet 12 provides the down range toughness to deliver controlled expansion at close and long range distances. Its recessed receiving portion 26 provides a cradle for jacket runner 14, securing it therearound by means of a tension pressure fit or the like, or other suitable means. Shoulders 32,34 prevent the forward or rearward movement of jacket runner 14 during loading and firing of the projectile. In addition, the two shoulders 32, 34, the outward most ends of which are preferably the greatest outer diameter of bullet 12, also act as a guide within the barrel facilitating the centering of projectile 10 within the bore of the firearmn. This greatest outer diameter of bullet 12 is slightly less than the primary bore of the firearm, and can be approximately half a thousandth of an inch smaller. The outer diameter of jacket runner 14 when positioned on bullet 12 is greater than the primary bore diameter. Thus, jacket runner 14 limits contact between the barrel and bullet 12, reducing or eliminating scoring of the metal, which can cause fouling of the firearm barrel. Further, when inserted into the bore or fired from the barrel of a rifle, the malleability of the jacket runner material allows it to fill in the depth of the lands to the secondary bore dimension of the barrel. In this way, jacket runner 14 provides a gas checking function, and in combination with shoulders 32, 34 of bullet 14, provides for centering of the projectile 10 in the barrel. Thus, the combination bullet 12 and jacket runner 14 work together to provide the correct alignment of the projectile 10 in the center of the barrel, and efficient gas checking from the ignition of the powder charge, and since jacket runner 14 remains on bullet 12 throughout its flight, this combination also provides rotational stability of the projectile in flight to give it enhanced down range accuracy.

The manufacturing process for runners 14, 114, 214 and 314 formed from materials incorporating synthetic or other elastic materials can achieve high speed, cost effective mass production, whereas a runner formed from metal, porcelain or other such materials which cannot stretch and does not have elastic memory properties, would require manufacturing in multiple pieces for installation onto the recessed receiving portion of the bullet. Accordingly, the projectile in accordance with the present invention, due to the flexibility and elasticity of the jacket runner, is highly suitable for the high speed manufacture of small sizes and calibers of projectiles.

It is understood that the projectile of the present invention is useful for any of a number of small munitions applications. These can include, but are not limited to, muzzle loader firearms, slugs for shot guns, centerfire or rimfire rifles, and center fire or rimfire handguns. Projectiles for any such applications incorporating the bullet and jacket runner configuration of the present invention are deemed to be within the scope of this invention.