Abstract:
An improved muzzleloading firearm provided with a combustion chamber of a diameter greater than its bore. The larger diameter of the combustion chamber provides for more efficient burning of the powder. The improved combustion chamber is used in association with an improved breech plug and ignition stem which simultaneously prevents a projectile from entering the combustion chamber, and ignites the powder in the combustion chamber from the muzzle end of the powder charge, producing a more efficient burn.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates in general to an improved combustion chamber for muzzleloading firearms and, more particularly, to a combustion chamber of increased diameter and means for preventing a projectile from entering the combustion chamber.  
         [0003]     2. Description of the Prior Art  
         [0004]     It is known in the art to provide centerfire rifle cartridges with short, fat cases. Concentrating the propellant in this manner produces a more efficient burn and transfers more power to the bullet. One drawback associated with such systems is that they ignite the propellant from the breech end of the propellant charge. By igniting the breech end of the propellant charge, the gases initially expanding near the breech end must dissipate some of their power in an effort to move unburned propellant toward the muzzle. Although it would be more efficient to ignite the propellant charge from the muzzle end of the charge, present technology has not provided a mechanism for such an ignition system.  
         [0005]     While such short, fat propellant charges, namely charges with a diameter greater than the bullet or projectile are desirable, it has not heretofore been known to utilize this efficiency in muzzleloading firearms. Because muzzleloading firearms do not utilize a case, the bullet or projectile cannot be “crimped” or otherwise locked against undesired movement into the larger combustion chamber which holds the propellant. If the bullet were not so secured, in a muzzleloading situation the bullet may inadvertently move into the combustion chamber. If the combustion chamber were of a greater diameter than the bore, the bullet may become inadvertently wedged against the transition between the combustion chamber and the bore of the firearm. If the propellant charge were to ignite and the bullet were to become wedged against movement down the bore, a potentially hazardous situation could result in a bulge and destruction of the barrel, or, more seriously, to a rupture of the barrel, causing serious injury and possibly death.  
         [0006]     Accordingly, while it would be desirable to provide a muzzleloading firearm with the efficiencies associated with a shorter, fatter charge, it has not heretofore been known in the art to provide a mechanism for utilizing such an efficient charge in muzzleloading firearms, while avoiding the dangers associated with potential barrel failure. Additionally, it would be desirable to provide a mechanism for igniting a propellant charge from the muzzle end of the charge as opposed to the breech end of the charge, to obtain added efficiencies associated with not having to propel unburned propellant toward the muzzle.  
         [0007]     The difficulties encountered in the prior art discussed hereinabove are substantially eliminated by the present invention.  
       SUMMARY OF THE INVENTION  
       [0008]     In an advantage provided by this invention, a firearm with an improved combustion chamber is provided, which is of a low cost manufacture.  
         [0009]     Advantageously, this invention provides a firearm with an improved combustion chamber which provides more efficient burning of a propellant charge.  
         [0010]     Advantageously, this invention provides a firearm with an improved combustion chamber which provides greater projectile velocity.  
         [0011]     Advantageously, this invention provides a firearm with an improved combustion chamber which prevents inadvertent movement of a projectile into the combustion chamber.  
         [0012]     Advantageously, this invention provides a firearm with an improved combustion chamber for a muzzleloading firearm which may be adapted to existing muzzleloading firearm technologies;  
         [0013]     Advantageously, in a preferred example of this invention, an improved muzzleloading firearm is provided. The firearm is provided with a barrel having an interior of a first diameter coupled in fluid communication with a combustion chamber having a second diameter, wherein the second diameter is greater than the first diameter. The firearm is also provided with a trigger and an ignition system which provides ignition to the combustion chamber upon actuation of the trigger. In the preferred embodiment, the firearm is provided with an ignition stem which extends into the combustion chamber to ignite the muzzle end of the powder and prevent a projectile from entering into the combustion chamber a sufficient distance to become lodged therein. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     The present invention will now be described, by way of example, with reference to the accompanying drawing in which:  
         [0015]      FIG. 1  illustrates a rear perspective view of the improved firearm of the present invention;  
         [0016]      FIG. 2  illustrates a side elevation in cross-section of the improved barrel of the firearm of  FIG. 1 , shown with the breech plug removed;  
         [0017]      FIG. 3  illustrates a side elevation in cross-section of the improved barrel and combustion chamber of the present invention, shown with the breech plug inserted, the combustion chamber filled with powder, and a patched bullet inserted into the bore;  
         [0018]      FIG. 4  illustrates a side elevation in cross-section of an alternative embodiment of the barrel and combustion chamber of the present invention, shown with a frustoconical combustion chamber and a cylindrical bullet. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0019]     A muzzleloading firearm according to the present invention is shown generally as ( 10 ) in  FIG. 1 . The firearm includes a stock ( 12 ) coupled to a receiver ( 14 ), which houses a trigger assembly ( 16 ). The firearm ( 10 ) is also provided with a barrel ( 20 ) having an ignition system ( 18 ). The stock ( 12 ), receiver and trigger assembly may be of any type known in the art.  
         [0020]     As shown in  FIG. 2 , the barrel ( 20 ) is provided with a breech end ( 22 ), and a breech plug retainer ( 24 ) provided with threads ( 26 ). In fluid communication with the breech plug retainer ( 24 ) is a combustion chamber ( 28 ). Although the combustion chamber ( 28 ) may be constructed of any suitable dimensions, in the preferred embodiment, the combustion chamber ( 28 ) is sized to receive an ignition stem ( 30 ) of a breech plug ( 32 ) as described below, and a propellant, such as a charge of black powder ( 34 ). Although the charge may be any suitable propellant known in the art, in the preferred embodiment the charge is 70 to 150 grains of black powder ( 34 ), or equivalent propellant, more preferably 90 to 130 grains of black powder ( 34 ), and most preferably, between 115 and 125 grains of black powder ( 34 ).  FIG. 3 .  
         [0021]     As shown in  FIG. 2 , the combustion chamber ( 28 ) transitions into the bore ( 36 ) of the barrel ( 20 ) by means of a step ( 38 ). While the bore ( 36 ) is sized with a diameter designed to accommodate a projectile ( 44 ) of a predetermined caliber, the combustion chamber ( 28 ) is preferably sized with a diameter at least 0.5% larger than the caliber of said projectile, more preferably at least 1.0% larger than the caliber of said projectile, and, most preferably at least ______% larger than the caliber of said projectile. The transition between the combustion chamber ( 28 ) and the bore ( 36 ) preferably takes place over a distance of ______ mm or less and at an angle of ______ degrees or steeper.  
         [0022]     As shown in the drawings, the bore ( 36 ) is provided with lands ( 40 ) and grooves ( 42 ) which make up the rifling of the bore ( 36 ), and which stabilize the projectile ( 44 ), which may be a patched lead bullet, a sabot jacketed round or any other projectile known in the art. The bore ( 36 ) may be of any diameter known in the art, but is preferably greater than 32 caliber, more preferably greater than 44 caliber, and most preferably of a caliber ranging between 45 caliber and 54 caliber.  
         [0023]     The length of the combustion chamber ( 28 ) is sized to accommodate the ignition stem ( 30 ) and the desired amount of power ( 34 ) for the desired diameter. Preferably, the dimensions are provided so that the length of the combustion chamber ( 28 ) and ignition stem ( 30 ) co-act to prevent the center line of the bullet ( 44 ) from extending rearward past the step ( 38 ) into the combustion chamber ( 28 ). If the bullet ( 44 ) is provided of a cylindrical configuration, such as that shown in  FIG. 4 , the length of the ignition stem ( 30 ) and combustion chamber ( 28 ) are sized to prevent any part of the bullet ( 44 ) from extending past the step ( 38 ) into the combustion chamber ( 28 ).  
         [0024]     If the combustion chamber ( 28 ) is too long in relationship to the ignition stem ( 20 ), the bullet ( 44 ) may accidentally be pushed into the combustion chamber ( 28 ) where, upon ignition of the powder ( 34 ), the bullet ( 44 ) may become wedged in the combustion chamber ( 28 ), causing a malfunction and possible bulging or even rupture of the barrel ( 20 ). Although the combustion chamber ( 28 ) is preferably cylindrical, it may, as shown in  FIG. 4 , frustoconical. Alternatively, the combustion chamber may be of an inverse frustoconical, or dual frusta conical “hourglass” configuration.  
         [0025]     When it is desired to utilize the present invention, the breech plug ( 32 ) is inserted into the breech plug retainer ( 24 ). As shown in  FIG. 3 , the breech plug ( 32 ) is provided with a plurality of threads ( 46 ) which fit into mating engagement with the threads ( 26 ) of the breech plug retainer ( 24 ). As shown, the breech plug ( 32 ) is provided with a nipple ( 48 ). A bore ( 50 ), extends from the nipple ( 48 ), through the breech plug ( 32 ) and through the ignition stem ( 30 ) to an outlet ( 52 ). As shown in  FIG. 3 , the outlet ( 52 ) is preferably of a diameter smaller than the bore ( 50 ) to allow sufficient ignition of the powder ( 34 ), while preventing backpressure from moving rearwardly through the bore ( 50 ). While the ignition stem ( 30 ) may be of any desired dimensions, in the preferred embodiment, the ignition stem ( 30 ) and bore ( 50 ) are cylindrical, having a diameter of ______ mm. The bore ( 50 ) is also preferably cylindrical, having a diameter of ______ mm. The breech plug ( 32 ) and ignition stem ( 30 ) are preferably formed into an integral piece of stainless steel, or other material known in the art.  
         [0026]     Once the breech plug ( 32 ) has been installed, to load the firearm ( 10 ), a predetermined amount of powder ( 34 ),  120  grains in the preferred embodiment, is measured and dropped into the combustion chamber ( 28 ), through the muzzle ( 58 ).  
         [0027]     A patch ( 56 ) is then placed over the muzzle ( 58 ) and the bullet ( 44 ) is placed over the patch ( 56 ). The bullet ( 44 ) is thereafter thrust into the bore ( 36 ) of the barrel ( 20 ) by utilizing a bullet starter (not shown), or any other method known in the art. Thereafter, the bullet ( 44 ) and patch ( 56 ) are forced through the bore ( 36 ) by the ramrod ( 60 ) until the patch ( 56 ) sufficiently compacts the powder ( 34 ).  FIGS. 1-3  The ramrod ( 60 ) is removed and a percussion cap ( 54 ) is provided over the nipple ( 48 ). Although a percussion cap ( 54 ) is utilized in the preferred embodiment, a musket cap,  209  shotgun primer or any suitable ignition means known in the art may be utilized.  
         [0028]     As shown in  FIGS. 1 and 3 , when it is desired to fire the firearm, a hammer ( 74 ), such as any type of hammer known in the art, is cocked, and a trigger ( 76 ) of the firearm ( 10 ) is actuated to drop the hammer ( 74 ) on the percussion cap ( 54 ), thereby igniting the percussion cap ( 54 ) and sending an ignition charge ( 78 ) through the bore ( 50 ) and outlet ( 52 ) of the breech plug ( 32 ) and ignition stem ( 30 ). The ignition charge ( 78 ) ignites the powder ( 34 ), which burns back toward the breech plug ( 32 ). This ignition causes the expansion of gasses within the combustion chamber ( 28 ), thereby propelling the bullet ( 34 ) down the bore ( 36 ) and out the muzzle ( 58 ).  
         [0029]     If an insufficient amount of powder ( 34 ) is provided to prevent the bullet ( 44 ) from entering the combustion chamber ( 28 ), the ignition stem ( 30 ) contacts the bullet ( 44 ), thereby preventing the bullet ( 44 ) from becoming inadvertently lodged in the combustion chamber ( 28 ) during ignition and causing a malfunction. As shown in  FIG. 2 , the ignition stem ( 30 ) ignites the muzzle end of the powder ( 34 ). Accordingly, as the powder ( 34 ) ignites from the muzzle end of the combustion chamber ( 28 ) and burns toward the breech end of the powder ( 34 ), the expanding gases propel little, if any of the unburned powder ( 34 ) through the bore ( 50 ). This results in efficient ignition as the power of the combustion is not wasted in transporting the powder ( 34 ), but is substantially wholly directed toward transporting the bullet ( 44 ) through the bore ( 50 ) and out the muzzle ( 58 ) of the firearm ( 10 ).  
         [0030]     An alternative embodiment of the present invention is shown generally as ( 62 ) in  FIG. 4 . In this embodiment, the combustion chamber ( 64 ) is provided of a substantially frustoconical design, tapering from the breech plug ( 66 ) toward the bore ( 68 ). As shown in  FIG. 4 , a cylindrical bullet ( 70 ) may be utilized with an ignition stem ( 72 ) sized to prevent entry of the bullet ( 70 ) into the combustion chamber ( 64 ).  
         [0031]     Although the invention has been described with respect to a preferred embodiment thereof it to be also understood that is not to be so limited, since changes and modifications can be made therein which are within the full, intended scope of this invention as defined by the appended claims. Of course, it should be noted that the present invention may be utilized in association with any desired muzzleloading trigger assemblies, hammers, ignition systems, breech plugs, propellants, bullets and or bores known in the art.