Patent Application
20120318123
Not applicable
Not applicable
The present invention generally relates to ammunition for muzzle-loader firearms, and more particularly to propellant charges having a consumable cartridge case. Some embodiments are directed to the manufacture and methods of use of such devices.
In muzzle-loader firearms, multiple ammunition components are loaded from the open end of the barrel. These multiple components include at least a propellant charge and projectile. The propellant charges comprise an amount of black powder, black powder substitutes, and smokeless gunpowder. The projectile typically comprises a bullet and a sabot. In some instances, the projectile and the propellant charge are inserted into the barrel as a unitary structure. Alternatively, the propellant charge is loaded separately from the projectile. In such instances, the propellant charge is loaded first into the barrel, followed by the sabot and the bullet.
The propellant charges are loaded into the barrel either in a granular form or in a compacted or consolidated pellet. The pellet allows for a simple, accurate and precise measurement of the propellant. U.S. Pat. Nos. 5,726,378 and 6,688,232, incorporated by reference in their entireties herein, describe exemplary pellets. In either the granular form or the pellet, the propellant is susceptible to moisture absorption and other environmental effects that can result in undesirable ballistic variation and corrosion of the firearm barrel and chamber.
The art referred to and/or described above is not intended to constitute an admission that any patent, publication or other information referred to herein is “prior art” with respect to this invention. In addition, this section should not be construed to mean that a search has been made or that no other pertinent information as defined in 37 C.F.R. §1.56(a) exists. All U.S. patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.
The present invention prevents exposure of the propellant to moisture and other environmental effects with enhanced ignition and ballistic reproducibility capabilities. A propellant charge comprises a sealed combustible container comprised of a consumable material and having a substantially cylindrically shape. The sealed combustible container comprises a top wall, a bottom wall, and a side wall therebetween. The top wall, the bottom wall and the side wall define a chamber; wherein the chamber contains a propellant composition. In at least one embodiment, the consumable material is a foamed celluloid. In at least one embodiment, the propellant composition is selected from the group consisting of: smokeless propellant, single base nitrocellulose, nitrocellulose propellant, black powder propellant, pyrotechnic propellant, non-pyrotechnic propellant, and any combination thereof.
In at least one embodiment, an ammunition round for a muzzle-loader is provided. The ammunition round comprises a bullet and at least one propellant charge having an outer wall constructed from a consumable material. The outer wall defines a chamber that is at least partially filled with at least one propellant composition having a charge weight.
This invention contemplates a number of embodiments where any one, any combination of some, or all of the embodiments can be incorporated into ammunition. In addition, this invention contemplates a number of embodiments where any one, any combination of some, or all of the embodiments can be incorporated into a method of using such ammunition.
Referring now to
Depending on the propellant requirements for a given muzzle-loaded firearm, the ammunition round can include one or more than one encapsulated propellant charge 106. In the embodiment shown in
The propellant 116 is selected from the group consisting of smokeless propellant, single base nitrocellulose, nitrocellulose propellant, black powder propellant, pyrotechnic propellant, non-pyrotechnic propellant, and any combination thereof. In at least one embodiment, the chamber 114 is substantially filled with the propellant 116.
In at least one embodiment, the ammunition round 100 is constructed and arranged with its rear portion positioned facing a breech block part of the muzzle loading firearm when loaded into a firearm. In some embodiments (such as the embodiment shown in
In at least one embodiment, the ammunition round is constructed and arranged to be used in combination with a primer or igniter separately positioned within a firearm barrel. When the firearm is triggered, a hammer strikes the primer material which ignites the primer material, resulting in an expulsion of a high temperature energetic jet of combustion products that penetrates the end of the capsule to ignite the encapsulated propellant charge. In other embodiments of the invention, the breech block penetrates an end of the capsule 110 of the encapsulated propellant charge 106 with a probe 120 or bayonet having a sharp point that forms a hole which allows hot materials from the ignited primer to enter the chamber 114 and ignite the propellant 116. The probe 120 can be tubular with a conical tip, can be conical, can be serrated, or can be any combination thereof, or can be of any shape known in the art. The ignition of the first encapsulated propellant charge 106a will ignite the second encapsulated propellant charge 106b. Ignition of the encapsulated propellant charges 106 provides the energy that propels the bullet 102 at a target. The capsule 110, which in at least one embodiment comprises a consumable material, is entirely consumed following ignition such that no portion of the capsule 110 remains.
In at least one embodiment, the capsule 110 has an axial length L that is greater than its diameter D. In at least one embodiment, the axial length L is twice the diameter D. In at least one embodiment, the axial length is at least three times the diameter D. In some embodiments, the wall thickness is dependent upon the caliber of the firearm being used. In some embodiments, the side wall 126 is thin-walled. In at least one embodiment, the thin-walled side wall 126 has a thickness of less than 0.05 inches (1.27 mm). In at least one embodiment, the side wall 126 has a thickness of between about 0.01 inches (0.254 mm) and 0.03 inches (0.762 mm). In at least one embodiment, the top wall 122 has a thickness of less than 0.05 inches (1.27 mm). In at least one embodiment, the top wall 122 has a thickness of between about 0.01 inches (0.254 mm) and 0.03 inches (0.762 mm). In at least one embodiment, the bottom wall 124 has a thickness of less than 0.05 inches (1.27 mm). In at least one embodiment, the bottom wall 124 has a thickness of between about 0.01 inches (0.254 mm) and 0.03 inches (0.762 mm).
In at least one embodiment, the diameter of the capsule is constant along the length of the capsule. In other embodiments, the diameter of the capsule tapers from a first end to a second end of the capsule. In one embodiment, the bottom wall 124 has an outer diameter that is tapered, as shown in
In at least one embodiment, the capsule has flat ends formed by the top wall and the bottom wall. In other embodiments, the capsule can have an arcuate surface at one end of the capsule. In another embodiment, the capsule can have an arcuate surface at each end of the capsule.
To manufacture the encapsulated propellant charge 106, in one embodiment, the capsule 110 is made using a thermoforming process. In at least one embodiment shown in
As shown in
In some embodiments, the sides of the sheet are fastened together in the cylindrical shape with an adhesive 150 forming the side wall 126, as shown in
A first circular disc 160 of the consumable material having a desired diameter is then adhered at one end 134 of the cylinder to form either the top wall 122 or the bottom wall 124, as shown in
As shown in
As shown in
In some embodiments, the solid circular discs 160, 164 can be replaced by caps that have a cavity that fits over the ends of the side wall 126. In at least one embodiment, the caps have an outer diameter that is greater than the diameter of the side wall 126. These caps are adhered to the side wall 126 using an adhesive such as cyanoacrylate and other suitable adhesives. In another embodiment, the caps are welded to the side wall using sonic welding, solvent welding, or other appropriate welding processes.
In another embodiment, the encapsulated propellant charge 106 is formed by vacuum thermoforming two portions of a cylinder each with one end enclosed by the mold design. After filling at least a portion of one of the cylindrical portions with the propellant, the two portions are adhered to one another with an adhesive such as cyanoacrylate or could be welded to together sonic welding, solvent welding, or other appropriate welding processes.
In some embodiments, a cylindrical tube of the consumable material can be extruded in relatively long tubes using a thermoplastic extrusion process, examples of which include a screw extruder or batch press with an associated annular extrusion die. The extruded cylindrical tube can then be cut to an appropriate length and closed on both ends using small end caps produced with a stamping operation. The small end caps are attached to the ends of the extruded cylinder using a mechanical fit, an adhesive, sonic welding, solvent welding, and other appropriate attachment processes In some embodiments, a first end cap can be attached to a first end of a cylindrical tube, the chamber can then be filled, and then a second small end cap would then be attached to a second end of the cylindrical tube to finished the sealed propellant charge. In at least one embodiment, as discussed above, a plate loader and/or other standard techniques in the industry can be used to fill the chambers of multiple cylinders simultaneously with a volumetrically measured amount of propellant. In one embodiment, the plate loader can also be used to fit the second small end cap on the second end of cylindrical tube. The second small end cap can then be adhered to the second end of the cylindrical tube to seal the propellant charge at a final sealing station with the adhesive or welding process.
In some embodiments, a sheet of the consumable material can be heated and wrapped around a mandrel to form a relatively long cylindrical tube, which can be cut to an appropriate length and closed on both ends using the small end caps discussed above. In at least one embodiment, multiple sheets of the consumable material can be wrapped around the mandrel in a spiral wrap to create a multi-layered cylinder that can be closed with the end caps discussed above.
In some embodiments, the encapsulated propellant charge 106 can be manufactured by injection molding at least a portion of the capsule into the desired shape.
In at least one embodiment, such as those embodiments shown in
In embodiments where the consumable material used in the propellant charge is a foamed celluloid, the aforementioned methods of manufacture assume that the foaming operation has been completed before shaping, and thus the sheets used to manufacture the encapsulated propellant charge comprise a foamed celluloid. In at least one embodiment, the sheets can comprise an unfoamed celluloid material with a foaming agent in the material and the foaming reaction can take place during the thermoforming or other shaping process where heat and pressure are applied. In an exemplary embodiment, the unfoamed celluloid material can be extruded into the long cylindrical tube and the foaming process would take place within the annular extrusion die under heat and pressure. The annular extrusion die would provide the necessary confinement of the material to control wall thickness, pore size, and density of the foamed celluloid material. In other embodiments, the unfoamed celluloid material is injected into a two part mold with cavities in the desired shape of the encapsulated propellant charge with the vacuum capability to expand the foam once it was pressed into the mold cavities.
Ballistic performance tests were conducted using standard market rifles equipped with pressure transducers and fired in a location equipped to measure muzzle velocity. The ballistic performance of the encapsulated propellant charge as described herein and a non-encapsulated charge is given in table 1 below:
As shown in the data presented above, the addition of the capsule had little effect on the average velocity of the projectile as compared to similar propellant charges that were not encapsulated.
Although the above disclosure describes the use of the encapsulated propellant charges in muzzle-loaded firearms, it is within the scope of the invention that appropriately sized encapsulated propellant charges as described herein may also be applicable to other ammunition such as tank rounds and caseless ammunition.
The above disclosure is intended to be illustrative and not exhaustive. This description will suggest many variations and alternatives to one of ordinary skill in this art. The various elements shown in the individual figures and described above may be combined or modified for combination as desired. Those skilled in the art may recognize other equivalents to the embodiments described herein, the equivalents of which are intended to be encompassed by the claims attached hereto. All these alternatives and variations are intended to be included within the scope of the claims where the term “comprising” means “including, but not limited to.”
