Abstract:
A consumable cartridge for a muzzle loading firearm having a consumable cartridge case composed of a consumable solid material is set forth. The cartridge case including a central internal cavity, the cartridge case having a closed first end and a second end open to the central internal cavity for receipt of granular, explosive powder within the central internal cavity of the cartridge case and a bullet is secured to the closed first end of the cartridge case. The cartridge case is shaped and dimensioned for positioning within a bore of a rifle along with the bullet.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of U.S. Provisional Application Ser. No. 60/647,429, filed Jan. 28, 2005, entitled “CONSUMABLE CASELESS CARTRIDGE FOR MUZZLE LOADING FIREARMS”. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates to cartridges for firearms. More particularly, the invention relates to consumable cartridges for muzzle loading firearms. 
     SUMMARY OF THE INVENTION 
     It is, therefore, an object of the present invention to provide a consumable cartridge for a muzzle loading firearm having a consumable cartridge case composed of a consumable solid material. The cartridge case includes a central internal cavity. The cartridge case has a closed first end and a second end open to the central internal cavity for receipt of granular, explosive powder within the central internal cavity. A paper disk covers the second end of the cartridge case to maintain the explosive powder within the central internal cavity of the cartridge case and a bullet is secured to the closed first end of the cartridge case. The cartridge case is shaped and dimensioned for positioning within a bore of a rifle along with the bullet. 
     Other objects and advantages of the present invention will become apparent from the following detailed description when viewed in conjunction with the accompanying drawings, which set forth certain embodiments of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of the consumable cartridge of the present invention attached to a bullet. 
         FIG. 2  is a side view of the consumable cartridge of the present invention separated from a bullet. 
         FIG. 3  is an exploded perspective view of the consumable cartridge of the present invention. 
         FIG. 4  is a side perspective view of the consumable cartridge of the present invention. 
         FIG. 5  shows an end view of two different embodiments of the consumable cartridge of the present invention showing the internal profile of the central internal cavity. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The detailed embodiments of the present invention are disclosed herein. It should be understood, however, that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, the details disclosed herein are not to be interpreted as limiting, but merely as the basis for the claims and as a basis for teaching one skilled in the art how to make and/or use the invention. 
     With reference to the various figures, a consumable cartridge  10  for a muzzleloader firearm is disclosed. The cartridge  10  includes a consumable cartridge case  12  and a bullet  14  that is secured to the first end  16  of the cartridge case  12  in a manner described below in greater detail. The present consumable cartridge  10  provides for the convenient firing of a muzzleloader rifle without the conventional requirement of loading powder and bullets in separate steps. In practice, the cartridge case  12 , with the explosive powder  18  therein, is ignited propelling the bullet  14  from the rifle bore as the cartridge case  12  is fully consumed by the heat generated during the explosion of the powder  18 . The explosive powder  18  may be the same or similar to that disclosed in U.S. Pat. Nos. 5,449,423 and 5,633,476 to Cioffe, which are incorporated herein by reference. As those skilled in the art will certainly appreciate, the term consumable as used herein indicates that the cartridge is fully destroyed as a result of the ignition of the explosive powdering during firing of a bullet. 
     The cartridge case  12  is shaped and dimensioned for positioning within the bore of a muzzleloader rifle. In particular, and in accordance with a preferred embodiment of the present invention, the outside diameter of the cartridge case  12  is approximately 0.001 inches to approximately 0.020 inches less then the bore diameter of the rifle. With this in mind, the cartridge case  12 , as well as the bullet  14 , may be manufactured in various calibers without departing from the spirit of the present invention. 
     The cartridge case  12  is generally cylindrical and includes a central internal cavity  20  shaped and dimensioned for receiving explosive powder  18 . As will be appreciated by those skilled in the art, the cavity shape employed in conjunction with the cartridge case  12  may take a variety of forms depending upon the desired charge characteristics. For example and as shown in  FIG. 5 , the cavity  20  may be round or square, but other shapes such as hexagonal, etc, are within the spirit of the present invention. In accordance with a preferred embodiment of the present invention, the cartridge case  12  has a wall thickness of approximately 0.025 inches to approximately 0.125 inches. 
     The cartridge case  12  includes a first end  16  and a second end  22 . The performance of the present cartridge  12  is enhanced by forming the central internal cavity  20  with a slight taper as it extends from the second end  22  of the cartridge case  12  to the first end  16  of the cartridge case  12  such that central internal cavity  20  adjacent the first end  16  is narrower than the central internal cavity  20  adjacent the second end  22 . In accordance with a preferred embodiment of the present invention, the taper is approximately 0.01 degrees to approximately 5.0 degrees. 
     The first end  16  is closed and is shaped and dimensioned for receiving the rearward end  24  of the bullet  14 . In accordance with a preferred embodiment of the present invention, the first end  16  is formed with a substantially frusto-conical shape, wherein the walls of the cone exhibit a slight concavity. The first end  16  is shaped and dimensioned to provide a friction fit with the rearward end  24  of the bullet  14  when the bullet  14  is secured thereto. 
     With this in mind, the bullet  14  is formed in a conventional manner with a pointed forward end  26  and a concave rearward end  24 . The concave rearward end  24  is shaped and dimensioned for receiving the frusto-conical projection  17  at the first end  16  of the cartridge case  12 . More particularly, the rearward end  24  of the bullet  14  and the first end  16  of the cartridge case  12  are dimensioned to frictionally engage each other in a manner securely holding the bullet  14  atop the cartridge case  12 . 
     While a frictional engagement structure is disclosed in accordance with a preferred embodiment of the present invention, other coupling techniques, for example, adhesive, may be used in conjunction with or as a replacement for the frictional engagement structure disclosed above. In addition, the present cartridge is contemplated for sale and use with the bullet secured to the cartridge case prior to placement within the rifle bore. However, those skilled in the art will appreciate that the cartridge case and bullet may remain separate and be loaded within the rifle bore sequentially prior to use. 
     The second end  22  of the cartridge case  12  is open providing ready access to the central internal cavity  20  for receiving the granular, explosive powder  18  used as a propellant in accordance with the present invention. Once the central internal cavity  20  of the cartridge case  12  is filled with granular, explosive powder  18 , the second end  22  is covered with a paper disk  28 . The paper disk  28  assists in maintaining the explosive powder within the cartridge case  12  and igniting the granular explosive powder  18 . In accordance with a preferred embodiment of the present invention, the paper disk  28  is composed of nitrocellulose paper, flash paper or nitrated paper. The paper disk  28  is secured to the second end  22  via nitrocellulose glue or other adhesive. 
     The cartridge case  12  is consumable and is composed of a mixture of nitrate salt, perchlorate salt and an organic fuel. The cartridge case  12  may also optionally include binders and other additives determined to improve manufacturing and performance. More particularly, and in accordance with a preferred embodiment, the cartridge case  12  is composed of potassium nitrate (approximately 20% to approximately 60% by weight), potassium perchlorate (approximately 0.5% to approximately 25% by weight, and, more preferably, approximately 15% to approximately 25% by weight) and organic fuel (approximately 25% to approximately 45% by weight). 
     The organic fuel is chosen from the group consisting of polyhydroxy-hydrocarbons (sugar alcohols), polyhydroxy-carboxylic acids (sugar acids) and salts thereof. More particularly, the fuel is ascorbic acid, erythorbic acid or other isomers of ascorbic acid or salt, ester or ether thereof. 
     As mentioned above, the cartridge case  12  may include binders. In accordance with a preferred embodiment, the binder is nitrated cellulose or other organic polymers. The binder is applied to the mixture in a quantity of approximately 0.5% to approximately 10% by weight. 
     The mixture may also include additives assisting in the performance of the cartridge case  12 . Included among these additives are carbon and graphite, which may function as a lubricant. The mixture may also be supplemented with the inclusion of plasticizers and combustion modifiers. 
     The cartridge case  12  is preferably formed by compressing the mixture described above in a mold under pressure from approximately 1,000 psi to 20,000 psi. As mentioned above, the cartridge case  12  is filled with an explosive powder  18 . In accordance with a preferred embodiment of the present invention, the powder  18  may also be the same as the mixture described above for use in the manufacture of the cartridge case  12 . However, the mixture for use as the explosive powder  18  is merely granulated to a fine powder and then compressed within the cartridge case to a density of approximately 1.5 to approximately 1.9 grams/cubic cm. 
     EXAMPLES OF APPLICATIONS OF THE PRESENT INVENTION 
     Example 1 
     
         
         
           
             A caseless cartridge of 100 grains weight, manufactured as described herein, was attached to a 50 caliber 348 grain Powerbelt™ and fired in a Knight Master Hunter™ rifle with Remington #209 primer. The resulting velocity (average of five shots) was 1776 feet per second with a standard deviation of 26 feet per second. 
           
         
       
    
     Example 2 
     
         
         
           
             A caseless cartridge of 100 grains weight, manufactured as described herein, was attached to a 50 caliber plastic sabot containing a 222 grain tungsten Thunderhead™ bullet and fired in a Knight Master Hunter™ rifle with Remington #209 primer. The resulting velocity (average of five shots) was 1905 feet per second with a standard deviation of 15 feet per second. 
           
         
       
    
     While the preferred embodiments have been shown and described, it will be understood that there is no intent to limit the invention by such disclosure, but rather, is intended to cover all modifications and alternate constructions falling within the spirit and scope of the invention.