Patent Application
20240418487
The inventive concepts disclosed herein relate generally to projectiles, and, more particularly, to jacketed projectiles having a hollow channel and manufacturing methods thereof.
Ammunition cartridges of the type commonly used in modern firearms are generally well known in the art. These ammunition cartridges typically include a cylindrical case that carries an internal payload, e.g., propellant powder, and has an open end for receiving a projectile. The size and shape of the cartridge and projectile will typically be dependent on the firearm used. The end opposite the projectile receiving end is typically closed about a means for igniting the internal payload, e.g., a primer disposed in the base end of a cartridge. When chambered in a firearm, the projectile engages the bore of the barrel and the base end faces a firing mechanism, e.g., firing pin. When the primer is struck by the firing pin, a flash is produced which ignites the propellant powder within the case to propel the projectile down the bore and out of the muzzle.
Ignition of the propellant powder releases a substantial amount of energy that is contained within the cartridge and the firing chamber. In normal working conditions, the path of escape for the released energy is out of the projectile receiving end of the cartridge. Thus, the energy propels the projectile down the bore, reaching substantial velocities, e.g., upwards of 3,000 feet per second. The projectiles must be durable enough to withstand the initial shock of energy propelling the projectile while also being aerodynamically efficient to travel through the air toward the desired target.
Projectiles, e.g., bullets, are typically made from malleable metallic materials such as lead and are seated in a jacket. A lead core is typically seated in a cup-shaped disc of jacket material prior to being formed into the desired shape. Traditionally, the jacket and core pass through a series of mechanical die presses that stretch and form the material into the final shape. Conventionally, the jacket is made from copper and substantially encloses the core. In some bullet types, the jacket extends past the nose of the core and is thereafter folded or crimped back in on itself forming a hollow point. In other types, the jacket may be pointed or rounded. The shape of the bullet is dependent on the desired use and the firearm with which it will ultimately be fired from. Regardless of the bullet shape, the bullet will experience some degree of air resistance as it travels through the air.
Thus, what is needed is an aerodynamically stable bullet that is designed to substantially reduce the air resistance experienced by the bullet during flight.
The inventive concepts disclosed herein relate to an aerodynamically improved projectile that has an engineered design to reduce air resistance while simultaneously reducing the overall projectile mass to achieve higher velocities. The projectile can be a jacketed projectile made from conventional materials, e.g., copper jacket surrounding lead core, or can come in the form of a metal powdered core that has a polymer jacket manufactured according to conventional injection molding techniques. The projectile can be made in any conventional or unconventional caliber size or shape.
In one embodiment, the disclosed projectile includes a core that is open-ended and has a channel defined from the open forward end through the core to the open base end. The jacket covers the core and has a nose opening and base opening that are axially aligned with the channel. A removably attachable base cover is attached to the base opening of the jacket. In preferred embodiments, the base cover completely blocks the base opening and is concentrically aligned with the channel. The channel is preferably cylindrical and has a uniform internal diameter.
The base cover can include a shaft extending from the cover and into the channel. In some embodiments, the shaft may have a longitudinal length of 0.001 inches to 0.150 inches. The exact length of the shaft will be dependent on the caliber of projectile formed, where larger caliber projectile require longer shafts. The shaft can be tapered and can frictionally engage with the channel. The base cover is engineered to detach from the projectile during flight, after the projectile has been fired from the ammunition cartridge. In preferred embodiments, the base cover detaches from the base opening under force of air pressure entering the channel during flight.
The forward end projectile can have an inward taper toward the longitudinal centerline of the projectile such that an ogive is formed. Similarly, the base end of the projectile can be formed with a boat tail, e.g., a rearward inward taper toward the longitudinal centerline. Alternatively, the base end can be formed flat.
In another aspect, the inventive concepts relate to a method for manufacturing the aerodynamically improved projectile. The jacket is formed with the nose opening and the base opening. The core is thereafter formed and disposed within the jacket. Note, these steps can be accomplished according to conventional bullet manufacturing processes using a series of mechanical die presses that stretch and form the jacket and core into the desired shape. Alternatively, the jacket and core can be formed using conventional injection molding techniques. In such a process, the jacket is formed first in a mold and the core is thereafter injected into the jacket from the nose opening so that the core is substantially enclosed. Next, the channel is bored through the core from the nose opening to a base opening defined through the base end of the jacket. This can be done by drilling out the channel or can be done simultaneously when the core is injection molded into the jacket based on the mold design of the core, e.g., a cylindrical rod can extend from the nose opening to the base opening of the jacket so that the core is molded within the jacket and the rod defines the channel therethrough. Alternatively, the core can be formed from a one or more metal powders in a mechanical press. A dowel is positioned substantially centrally in the mechanical press to define a concentrically aligned channel therethrough. The jacket and the core pass through a series of die presses that stretch and form the jacket and powder core into the desired shape.
In subsequent steps, the base cover can be removably attached to the base opening. Attachment of the base cover can be done by adhesively attaching it to the base end of the projectile. Or, more preferably, the base cover includes a shaft that will frictionally engage within the channel and be mechanically pressed therein from the base end.
Other systems, methods, features and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims. Component parts shown in the drawings are not necessarily to scale, and may be exaggerated to better illustrate the important features of the invention. Dimensions shown are exemplary only. In the drawings, like reference numerals may designate like parts throughout the different views, wherein:
The following disclosure presents exemplary embodiments of a projectile with increased aerodynamic efficiency. The disclosed projectile includes a channel defined substantially from the nose through the body to the base. The channel reduces the air resistance experienced during flight of the projectile. Further, a cover can be attached to an end of the projectile to protect the projectile from the explosive energy generated at the point of firing while still in the firearm. The cover is engineered to detach from the remainder of the projectile at some point during flight, thereby opening the channel from end-to-end through the projectile body. The disclosed projectile can be formed in any conventional shape known for bullets or other types of projectiles used in ammunition, e.g., flat base, boat tail base, round nose, pointed nose, hollow point nose, etc. The disclosed inventive concepts can readily be applied to projectiles of any conventional or unconventional caliber for ammunition projectiles, including those calibers for pistols, rifles or shotgun of military or civilian grade along with certain types of artillery shells.
Throughout this disclosure, the terms “polymer” and “synthetic polymer” and “synthetic coating” shall be interpreted in a non-limiting fashion and given a broad interpretation according to their plain and ordinary meaning. “Polymer” can mean a natural polymer or a synthetic polymer, and any invention described herein that refers to a “synthetic polymer” may, in an alternative embodiment, substitute a natural polymer for the synthetic polymer and vice versa. Examples of polymers as used herein include but are not limited to acrylic, polyethylene, polyolefin, polypropylene, polystyrene, polyvinylchloride, synthetic rubber, phenol formaldehyde, neoprene, nylon, polyacrylonitrile, PVB, silicone, and any of the foregoing in powdered, micronized powdered, or resin form.
The jacket 12 and the core 14 can be made from conventional projectile materials, e.g., copper jacket with a lead core, that are mechanically pressed into shape through a series of dies. Alternatively, the jacket 12 can be formed of polymer material that is injection molded over a core 14 made from lead or both the jacket and the core can be injection molded. In some embodiments, the core 14 may be injection molded from a mixture of metal powders, e.g., tungsten, aluminum, tin, zinc, etc., and the jacket 12 thereafter polymer injection molded around the core. These and other methods for making the projectile 10 are described in further detail below.
The channel 30 is engineered to reduce the air resistance experienced by the projectile 10 during flight after being fired from the firearm. The channel 30 extends through the entire longitudinal length of the projectile 10 and is open at the nose end 18 and the base end 20. The base cover 22 removably attaches to the projectile 10 at the base end 20 allowing the channel to fully open during flight, as detailed further below. The channel 30 also reduces the overall mass of the projectile 10, which allows the projectile to attain higher velocities in comparison to a conventional projectile of the same caliber. The reduction in air resistance in combination with a reduction to the overall mass of the projectile 10 results in a flatter trajectory path for a projectile traveling at a higher maximum velocity to thereby increase the overall accuracy of the projectile.
The removable attachment means of the base cover 22 is designed so that once the projectile 10 exits a firearm barrel, the base cover detaches, thereby allowing air entering the nose end 18 of the channel 30 to pass through the projectile body 26 and exit the opening at the base end 20. In some embodiments, the base cover 22 includes a shaft 38 that extends into the channel 30 and frictionally engages with the inner walls of the channel. The shaft 38 can be tapered from the base cover 22 to a distal end within the channel 30. Alternatively, the base cover 22 can be lightly adhered to the base end 20 using an adhesive. In further alternatives, the base cover 22 can be frangible such that when the cartridge is fired and the projectile 10 exits the barrel, the force of air pressure entering the channel 30 breaks the base cover causing it to detach. In more elaborate embodiments, the shaft 38 can have threads that allow the base cover 22 to detach upon exiting the barrel after firing. In such embodiments, the threads should be sufficient to maintain attachment of the base cover 22 to the projectile 10 throughout normal handling but break or otherwise disengage under the pressure differential created in the channel 30 during projectile flight.
In addition to the base cover 22 being engineered to detach from the projectile 10 during flight, it also serves to preserve the integrity of the projectile upon firing. As explained above, when an ammunition cartridge is fired, a significant amount of energy is released to propel the projectile 10 down the firearm barrel. The base cover 22 protects the projectile 10 from this energy by plugging the openings defined through the base end 20 that would otherwise expose the internal channel 30 to the gases and pressures generated during firing. Absent the base cover 22, the pressure could enter the channel 30 and cause the structural integrity of the projectile 10 to weaken to the point of failure in the barrel.
The pressure column created inside the firearm barrel to propel the projectile 10 ensures that the base cover 22 remains attached to the base end 20 while inside the barrel. Upon exiting the barrel, the pressure at the base end 20 drops, allowing the force of the air pressure entering the channel 30 at the nose end 18 to exceed the force of the attachment means used for the base cover, e.g., frictional engagement of the shaft 38 extending inside the channel 30, causing the base cover 22 to detach. The channel 30 is now fully open from the nose end 18 through to the base end 20, allowing air to pass therethrough and thus decreasing the amount of air resistance experienced during flight. With the channel 30 fully opened during flight, the projectile 10 will experience a fly wheel stabilization effect resulting in longer spin stability during flight, thus achieving a flatter trajectory to target.
Once the jacket 12 has been formed, the method 100 advances to step 114 to form the core 14 with the desired ogive 16 profile. The core 14 can be formed using conventional lead material that is passed through a series of mechanical die presses until the desired shape is achieved, as is known in the art. Alternatively, the core 14 can be molded according to conventional polymer or metal injection molding techniques, using any known polymeric or metallic powders suitable for such molding. At step 116, the core 14 is seated in the jacket 12. Step 118 involves forming the ogive 16 in the jacket 12 to substantially match the profile of the ogive in the formed core 14. Once the projectile 10 has been formed with its desired shape and the profiles of the jacket 12 substantially match the profiles of the core 14, the channel 30 is bored out through the core from the nose opening 28 to the base opening 32 (step 120). Preferably, the channel is axially aligned with the nose opening 28 and the base opening 32 and defined through the longitudinal centerline of the projectile 10. The channel 30 is preferably cylindrical in shape and can be formed by drilling from the nose opening 28 through the core 14 to the base opening 32.
In alternative methods, the core 14 may be formed from a one or more homogenously blended powders using one or more press dies. A dowel, having an outer diameter corresponding to the desired diameter of the channel 30, is positioned in the pre-formed jacket 12 so that the dowel at least partially extends through the nose opening 28 and the base opening 32. In some embodiments, the dowel may include a taper corresponding to the desired profile of the ogive 16. With the dowel positioned, the core in powdered form and the pre-formed jacket advance through the one or more mechanical die presses to form the desired projectile. The powder is compressed within the pre-formed jacket and about the dowel until the desired projectile profile has been achieved. The dowel is removed from the base end of the jacket prior to the projectile ejecting from the ogive forming die.
Note, these steps, steps 110 to 120, have been described in stepwise fashion but the skilled artisan will recognize that many can be done contemporaneously. For instance, the core 14 and the jacket 12 can be formed at the same time through the conventional process of mechanically die pressing the materials into the desired shape in a series of steps. Thereafter, the channel 30 can be drilled out from the nose opening 28 to the base opening 32, which can be formed as byproducts during the process of die pressing.
Once the projectile 10 has been formed and the channel 30 defined therethrough, the final step at step 122 is to plug the base opening 32 with the base cover 22. Depending on the type of base cover 22 being used, this can involve pressing the shaft 38 into friction fit engagement with the channel 30 through the base opening 32. In some embodiments, the shaft 38 can have a longitudinal length substantially equal to about 0.100 to 0.150 inches. However, the exact length of the shaft 38 may be dependent on the size of projectile being formed, where larger projectiles will require longer shafts. Alternatively, where the base cover 22 does not include the shaft 38, a small amount of adhesive can be applied at the base end 20 around the base opening 32. The base cover 22 can thereafter be pressed into contact with the adhesive to attach the cover to the base end 20. Regardless of the type of base cover 22 used, e.g., shaft or no shaft, it is preferred that the base cover be positioned about the base opening 32 to completely block the base opening 32 to protect the inside of the projectile during the firing process. The base cover can be made from any lightweight metal or polymer material.
Exemplary embodiments of the invention have been disclosed in an illustrative style. Accordingly, the terminology employed throughout should be read in a non-limiting manner. Although minor modifications to the teachings herein will occur to those well versed in the art, it shall be understood that what is intended to be circumscribed within the scope of the patent warranted hereon are all such embodiments that reasonably fall within the scope of the advancement to the art hereby contributed, and that that scope shall not be restricted, except in light of the appended claims and their equivalents.
