POLYMER PROJECTILE HAVING AN INTEGRATED DRIVING BAND
20200011643 ยท 2020-01-09
Inventors
- Erik K. Carlson (Oak Grove, MN, US)
- Joshua L. Edel (East Bethel, MN, US)
- Lawrence P. Head (Cambridge, MN, US)
Cpc classification
F42B12/40
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F42B5/145
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F42B30/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F42B33/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F42B12/76
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
F42B12/40
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F42B14/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F42B12/76
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F42B30/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F42B33/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
Abstract
A lightweight projectile having an integrated metal band positioned around the exterior of the polymer base of the projectile. The metal band may be a driving band that protrudes from the polymer base to minimize the contact between the polymer base and the rifling to reduce friction between the barrel and the projectile as the projectile is fired. The lightweight projectile may be propelled with less propellant force than conventional projectiles of the same caliber while still retaining the ballistic advantages of a spin stabilized projectile.
Claims
1. A lightweight projectile for firing from a 5.56 millimeter rifled barrel and in combination with a telescoping casing, the projectile adapted to be fired through a rifled barrel, comprising: a projectile defining a bullet shape and including: a polymer projectile body defining a sealed interior space and including a frangible polymer cap; a metal band that extends circumferentially around the polymer projectile body, the metal band including an embedded portion that extends inwardly into the polymer projectile body; and a marking media contained within the sealed interior space, wherein: the frangible polymer cap is configured to release the marking media on impact; and the weight of the projectile is less than 10 grains.
2. The lightweight projectile and casing of claim 1, wherein the metal band is a driving band.
3. The lightweight projectile and casing of claim 1, wherein the metal band provides 10 to 20% of the total weight of the projectile.
4. The lightweight projectile and casing of claim 1, wherein the metal band includes an exposed portion that extends radially outward from the embedded portion.
5. The lightweight projectile and casing of claim 4, wherein the exposed portion projects radially outward beyond the polymer projectile body to define a maximum radial dimension of the projectile, the exposed portion being a driving band configured to engage the rifling of the barrel to impart spin stabilization to the projectile.
6. The lightweight projectile and casing of claim 4 wherein the embedded portion has an axial thickness that is greater than an axial thickness of the exposed portion.
7. The lightweight projectile and casing of claim 4, wherein the exposed portion and the embedded portion are configured to define one of a T-shape and an L-shape when viewed in cross-section.
8. The lightweight projectile and casing of claim 4, wherein the exposed portion comprises a flexible material such that a portion of the exposed portion folds over upon engagement by the rifling of the barrel.
9. The lightweight projectile and casing of claim 1, wherein: the polymer projectile body includes a base that cooperates with the frangible polymer cap to define the interior space; and the metal band is positioned at a juncture between the frangible polymer cap and the base.
10. The lightweight projectile and casing of claim 1, wherein the metal band comprises one of aluminum, copper, and brass.
11. The lightweight projectile and casing of claim 1, wherein the metal band is adjacent to an outwardly protruding polymer rib extending from the polymer projectile body.
12. A cartridge for firing a lightweight projectile from a conventional firearm having a rifled barrel, comprising: a projectile comprising: a polymer projectile body including a cap and a base and defining an interior space; at least one metal band positioned on the polymer projectile body that extends circumferentially around the polymer projectile body, the at least one metal band including a projecting portion that extends in an axial direction along the polymer projectile body; and a marking media contained within the interior space, wherein: the polymer cap is configured to release the marking media on impact; and the weight of the projectile is less than 10 grains.
13. The cartridge of claim 12, wherein the at least one metal band is positioned on the base.
14. The cartridge of claim 13, wherein the at least one metal band includes a thin metallic layer.
15. The cartridge of claim 12, wherein: the cap and the base define and are concentric about a longitudinal axis, the projectile body adapted to rotate about the longitudinal axis; and the projecting portion extends in a direction radially outward from the longitudinal axis.
16. The cartridge of claim 15, wherein the projecting portion is configured to engage the rifling of a rifled barrel to impart spin stabilization to the projectile.
17. The cartridge of claim 12, comprising: a cartridge casing including an elongated hollow base that defines a first opening, a second opening, and a reduced diameter portion between the first opening and second opening; a polymer insert insertable into the first opening and defining a seating portion configured to receive the projectile; and a primer for generation of a gas when ignited, the primer being disposed proximate the second opening of the cartridge casing, the reduced diameter portion configured to direct the gas into a gas jet to propel the projectile out of the seating portion of the polymer insert.
18. A method of fabricating a lightweight projectile having an exterior surface and comprising a polymer and a rifled barrel of a firearm, comprising: forming at least one metal band, the metal band comprising one of brass and copper; positioning the at least one metal band in a mold for a first component of the projectile; and injecting polymer into the mold so that the metal band is at least partially embedded into the first component of the projectile.
19. The method of claim 18 comprising assembling the first component with a second component after putting marking material into the first component or the second component.
20. The method of claim 19, wherein the first component in the step of assembling is one of a base of the projectile and a cap of the projectile, and wherein the second component in the step of assembling is an other of the cap of the projectile and the base of the projectile.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The invention can be completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the accompanying drawings, in which:
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[0075] While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
DETAILED DESCRIPTION OF THE DRAWINGS
[0076] As shown in
[0077] The driving band 8 extends radially around the exterior of the projectile base 6. In one embodiment, the driving band 8 is positioned around the base portion 14 of the projectile base 6. A projecting portion 9 of the driving band 8 protrudes from outward from the projectile base 6 to engage the rifling of a barrel when the projectile 2 is fired. An embedded portion 11 of the driving band 6 is inset into the projectile base 6. In one aspect of the present invention, the driving band 6 comprises a cantilevered ring shape in which the driving band 6 is perpendicular to the axis of the projectile base 6 and the projecting portion 9 cantilevers radially outward from the projectile base 6 as shown in
[0078] As shown in
[0079] According to an embodiment, the projectile 2 can be sized to replicate the dimensions of the bullet for 5.5645 mm NATO (5.56 NATO) or .223 REMINGTON ammunition. The conventional bullets of 5.56 NATO cartridges and .223 REMINGTON have a diameter of 0.224 in (5.70 mm). According to an embodiment, the driving band 8 can have an outer diameter of 0.223 in (5.66 mm) and a thickness of 0.005 (0.127 mm) in such that the projecting portion 9 of the driving band 8 protrudes from the projectile base 6 for engaging the rifling of barrels sized for 5.56 NATO or .223 REMINGTON ammunition. In one aspect, the projectile base 6 can be dimensioned such that such that the outer diameter of the projectile base 6 is such that the projectile base 6 can travel through the barrel without engaging the rifling. According to an embodiment, the inner diameter of the driving band 8 can comprise 0.154 in (3.912 mm) such that the embedded portion 11 of the driving band 8 is seated within the projectile base 6.
[0080] Although the projectile 2 is sized to approximate the conventional equivalent, the weight of the projectile 2 is less than the conventional equivalent. A conventional bullet weight for a 5.56 NATO bullet can be about 4 grams. In one embodiment, the total weight of the projectile 2 for simulating 5.56 NATO bullet and containing a payload media can weight about 0.24 grams wherein the driving band 8 comprises about 15% of the total weight of the projectile 2; in other embodiments, from 10 to 20%. In aspect, the total weight of the projectile 2 with a payload media can be about 5 to 10% of the weight of the equivalent projectile. In another aspect, the total empty weight of the projectile 2 without a payload media can be about 1 to 5% of the weight of an equivalent conventional projectile 2. In embodiments the total weight of the projectile is less than 5 grains. In embodiments the total weight of the projectile is less than 6 grains. In embodiments the total weight of the projectile is less than 7 grains. In embodiments the total weight of the projectile is less than 10 grains. The inventors have discovered that projectiles of less than 4.25 grains may be fired from telescoping 5.56 mm practice cartridges as illustrated in
[0081] The projectile base 6 can comprise principally a thermoplastic polymer. Other embodiments can comprise ceramic material, compressed fibrous pulp, lightweight metal or other lightweight material that can be formed to define a projectile base 6. The driving band 8 can comprise a gilding metal, a more rigid polymer than that used to form the projectile base 6, a metal impregnated polymer or other composite material. According to an embodiment, the driving band can comprise 110 Copper (99.9% copper, 0.04% oxygen). Other materials include brass. The material of the driving band 8 provides more advantageous engagement characteristics than the base material of the projectile base 6. For example, better coefficient of friction with respect to firearm barrels, less sloughing of material, easier deformation to conform to the rifling of the barrel. The frangible cap 4 can comprise a frangible material, such as polystyrene, adapted to fracture upon impact with the target to release the payload within the cavity and/or reduce force with which the projectile 2 impacts the target.
[0082] In an embodiment of the present invention, the driving band 8 can serve to weight the exterior of the projectile base 6 to further facilitate spin stabilization of the projectile 2. The protruding portion 9 and/or the embedded portion 11 of the driving band 8 can be varied in size to increase or decrease the weight of the driving band 8 relative to the rest of the projectile 2 as shown in
[0083] As shown in
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[0090] The telescoping insert 38 comprises a telescoping portion 46 and a rim 48. The telescoping portion 46 is receivable within the second opening 42 such that the rim 48 is positioned against the second opening 42. The telescoping insert 38 defines a channel 50 for receiving the primer 32 and adapted to channel gases generated by igniting the primer 32 toward the projectile 2. According to an embodiment, the telescoping portion 46 can further comprise a gasket 52 engagable to the casing 34 to prevent gases from escaping between the telescoping portion 46 and the casing 34.
[0091] According to an embodiment, the cartridge casing 34 can define a flash hole 54 between the telescoping portion 46 and the projectile 2. During firing, the flash hole 54 compresses the gases generated by the ignited primer 32 into a gas jet, which propels the projectile 2 down the barrel of the firearm and to the target. Correspondingly, the projectile base 6 can define an indent 56 for capturing the gas jet to more efficiently fire the projectile 2 down the barrel.
[0092] During firing, the projectile 2 travels through the rifled barrel of the firearm such that the driving band 8 is engraved by the rifling of the barrel. The rifling imparts a spin to the projectile 2 such that the projectile 2 is spin stabilized once the projectile 2 leaves the barrel. In one aspect, the driving band 8 comprises a material of sufficient hardness such that projection portion 9 of the driving band 8 to be etched in the same way as a conventional bullet as shown in
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[0097] A method of making a non-lethal projectile with at least one driving band, according to an embodiment of the present invention, can comprise separately stamping or forming the driving band and the polymer base. The driving band can then be fitted over the polymer base to affix the driving band to the polymer base. Alternatively, the driving band can be placed in a mold and the projectile base or the base portion of the projectile base can be molded over the driving band. According to another embodiment, a polymer driving band can be over-molded onto a pre-molded polymer base. Powdered metal can be sintered onto a driving band on a polymer base.
[0098] All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.
[0099] While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and described in detail. It is understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.