BACKGROUND OF THE INVENTION  
       [0001]     1. Technical Field  
         [0002]     The invention relates generally to muzzle loading firearms wherein the breech end of the barrel is shaped to accept a blank cartridge case of the same or a different caliber than the bore of the muzzle. A gun barrel, projectile system, and method of using the same is also part of the invention.  
         [0003]     2. Related Art  
         [0004]     A long standing problem in the design of muzzle loading or black powder firearms is that the powder is exposed to the elements. This exposure results in degraded performance of the firearm due to powder which has been dampened or otherwise effected by the elements. Exposure to the elements is particularly a problem for hunters who are afield during inclement weather and must load their weapon during periods of rain or snow, all the while attempting to protect the powder and firing mechanisms. A related problem is that the powder charge receptacle is exposed and thus may be susceptible to inadvertent loss of part or all of the powder. To alleviate these problems, one must carry, in addition to the firearm, a complement of tools and accessories suited to keep the firearm in operable condition. These tools and accessories include loose powder in a container such as a powder horn or powder flask, loose primers, a nipple wrench, nipple picks, and breech plug tools.  
         [0005]     Thus, a need exists for a simple and reliable improvement to muzzle loading firearms, their barrel design, and projectile systems (i.e., charge and projectile) which overcome the aforementioned, and other, deficiencies associated with the related art.  
       SUMMARY OF THE INVENTION  
       [0006]     To overcome the above deficiencies, the present invention provides a muzzle loading firearm which fires a projectile having a first caliber, and which has a barrel bore shaped to accommodate the first caliber. The breech end of the firearm has a chamber which is shaped to accept a standard blank metallic cartridge case of the same or a different caliber of the projectile. The blank cartridge contains a primer and powder, but lacks a projectile. The cartridge chamber and the muzzle bore are connected by a suitably shaped opening. Upon discharge of the firearm, the powder charge from the cartridge case causes the projectile to be expelled from the muzzle.  
         [0007]     In a first general aspect, the present invention provides a gun barrel for use in a muzzle loading firearm, said gun barrel comprising: 
        a muzzle portion, characterized by a first caliber, said muzzle portion being configured to operationally receive a projectile;     a breech portion, characterized by a second caliber, said breech portion being configured to operationally receive a cartridge case; and     a connecting bore extending from said breech portion to said muzzle portion.        
 
         [0011]     In a second general aspect, the present invention provides a firearm comprising: 
        a muzzle portion, characterized by a first caliber, said muzzle portion being configured to operationally receive a projectile;     a breech portion, characterized by a second caliber, said breech portion being configured to operationally receive a cartridge case; and     a connecting bore extending from said breech portion to said muzzle portion.        
 
         [0015]     In a third general aspect, the present invention provides a muzzle-end loading firearm comprising: 
        a breech end configured so that a charge is loaded from said breech end; and     a muzzle end configured so that a projectile is loaded from said muzzle end.        
 
         [0018]     In a fourth general aspect, the present invention provides a substantially cylindrical gun barrel for use in a muzzle loading firearm, said gun barrel comprising: 
        a muzzle end, and a breech end;     a central bore extending from said muzzle end towards said breech end, said central bore characterized by a first caliber;     a mounting portion adjacent said breech end, said mounting portion configured for mounting said gun barrel to a firearm receiver;     a chamber adjacent said breech end, said chamber coaxial with said central bore, said chamber configured to operationally receive a cartridge case; and     a passage bore adjacent and between each of said central bore and said chamber, said passage bore communicating between said central bore and said chamber, said passage bore having a smaller diameter than said central bore.        
 
         [0024]     In a fifth general aspect, the present invention provides a method of increasing the reliability of a muzzle loading firearm, the method comprising: 
        providing a gun barrel with a muzzle end and a breech end, said muzzle end having a central bore characterized by a first caliber, said central bore extending from said muzzle end towards said breech end;     providing a mounting portion of said gun barrel adjacent said breech end, said mounting portion configured for mounting said gun barrel to a firearm receiver;     providing a breech end chamber of said gun barrel adjacent said breech end, said breech end chamber coaxial with said central bore, said breech end chamber configured to operationally receive a cartridge case; and     providing a passage bore of said gun barrel adjacent and between each of said central bore and said breech end chamber, said passage bore communicating between said central bore and said breech end chamber, said passage bore having a smaller diameter than said central bore;     providing a stock operatively coupled to said gun barrel and said firearm receiver, said stock including a trigger assembly operatively coupled to said firearm receiver and to a firing pin assembly; and     configuring said firing pin assembly to operatively interact with said cartridge case, when appropriate, to cause discharge of said muzzle loading firearm.        
 
         [0031]     The sixth general aspect, the present invention provides a projectile system, adapted for use with a muzzle loading firearm, comprising: 
        a cartridge of a first caliber containing a charge, adapted for loading in a breech end of said firearm; and     a projectile of a second caliber, adapted for inserting in a muzzle end of a gun barrel of said firearm.        
 
         [0034]     The foregoing and other features and advantages of the invention will be apparent from the following more particular description of embodiments of the invention. It is to be understood that both the foregoing general description and the following detailed description are exemplary, but are not restrictive, of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0035]     The features of the present invention will best be understood from a detailed description of the invention and an embodiment thereof selected for the purposes of illustration and shown in the accompanying drawings in which:  
         [0036]      FIG. 1A  is a side sectional view of a first type of gun barrel of the related art;  
         [0037]      FIG. 1B  is a side sectional view of a second type gun barrel of the related art;  
         [0038]      FIG. 2  is a sectional elevational view of cartridge case of the related art;  
         [0039]      FIG. 3A  is a side sectional view of a first embodiment of a gun barrel, in accordance with the present invention;  
         [0040]      FIG. 3B  is a side sectional view of a second embodiment of a gun barrel, in accordance with the present invention;  
         [0041]      FIG. 3C  is a side sectional view of a third embodiment of a gun barrel, in accordance with the present invention;  
         [0042]      FIG. 4A  is a close-up side sectional view of a breech portion of the gun barrel shown in  FIG. 3A , in accordance with the present invention;  
         [0043]      FIG. 4B  is a close-up side sectional view of a breech portion of the gun barrel shown in  FIG. 3B , in accordance with the present invention;  
         [0044]      FIG. 5A  is a side sectional view of a first embodiment of a projectile system, in accordance with the present invention;  
         [0045]      FIG. 5B  is a side sectional view of a second embodiment of a projectile system, in accordance with the present invention;  
         [0046]      FIG. 5C  is a side sectional view of a third embodiment of a projectile system, in accordance with the present invention;  
         [0047]      FIG. 6A  is a side section view of a first embodiment of a gun barrel and projectile system, in accordance with the present invention;  
         [0048]      FIG. 6B  is a side section view of a second embodiment of a gun barrel and projectile system, in accordance with the present invention; and  
         [0049]      FIG. 7  is a perspective view of a firearm with a gun barrel, in accordance with the present invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0050]     Although certain embodiments of the present invention will be shown and described in detail, it should be understood that various changes and modifications may be made without departing from the scope of the appended claims. The scope of the present invention will in no way be limited to the number of constituting components, the materials thereof, the shapes thereof, the relative arrangement thereof, etc., and are disclosed simply as an example of an embodiment. The features and advantages of the present invention are illustrated in detail in the accompanying drawings, wherein like reference numerals refer to like elements throughout the drawings.  
         [0051]     Referring to the drawings, and Figures IA and  1  B, in particular, which depict side sectional views of typical gun barrel with loading chambers known in the art. Both  FIGS. 1A and 1B  depict a gun barrel  100  with a muzzle end  104  and at the distal end, a breech end  103 . Both gun barrels  100  have a bore  101 .  
         [0052]      FIG. 1A  shows the gun barrel  100  that might be used in a typical “modern” breech-end loading gun barrel design, such as for a 0.308 rifle. That is a projectile “system” (not shown), which includes a cartridge case having a powder charge and a projectile, is totally loaded from the breech end  103  of the gun barrel  100  into a chamber  102  that is configured to match the shape and size of the projectile system inserted therein. Upon the firing of a weapon (not shown) with the gun barrel  100  shown, the projectile (not shown) is ejected towards the target from the muzzle end  104 . In the “traditional” embodiment, the caliber of the bore  101  is smaller than that of the chamber  102 . That is the cartridge case, containing a charge therein, is of larger diameter than the diameter of the projectile. The caliber of the projectile typically matches that of the bore  101 , while the caliber of the actual cartridge case matches that of the chamber  102 .  
         [0053]      FIG. 1B , contrastingly, shows a gun barrel  100  that is used in a typical “modem” in-line muzzle-loading firearm, such as a black powder rifle. The gun barrel  100  has a bore  101  that has at one end a muzzle end  104  at which both the powder and projectile is loaded. At the distal end of the barrel  100  is a breech end  103  which includes a series of threads  106  which allows for the threaded insertion in the breech end  103  of a breech plug  105 . The breech plug  105  includes a primer  107  opening from which the powder is activated. Upon the activation of the powder, the projectile is ejected towards the intended target.  
         [0054]     Referring now to  FIG. 2 , a brief description of a cartridge case of the related art is presented. A typical cartridge case  200  may include the following elements: mouth  210 , neck  220 , shoulder  230 , first element  240 , flash hole  250 , web  260 , extractor groove  270 , primer pocket  280 , second element  290 , and powder charge  295 . A bullet, or projectile, (not shown) may be seated in mouth  210 . In operation, a primer (not shown) is seated in the primer pocket  280 . When the primer is forcefully struck by a firing pin of a firearm, the primer ignites and in turn causes the powder charge  295  to controllably explode, thus forcing a bullet (not shown) from the muzzle of the firearm. Cartridge cases such as cartridge case  200  may be found in a variety of configurations, including straight-walled versions which lack the shoulder area. Cartridge cases may also be had in a variety of sizes depending on the size or designated caliber of their corresponding bullet.  
         [0055]     The present invention improves upon the related art and offers distinct, and numerous, advantages beyond it. The present invention may be employed with virtually any firearm, such as rifle, smoothbore musket, pistol, revolver, shotgun, grenade launcher, or the like.  
         [0056]      FIGS. 3A, 3B , and  3 C, contrastingly, depict side sectional views of three different embodiments of a gun barrel of the present invention. While all the embodiments, when integrated with a firearm, may be termed the “McGivern Muzzle-Loading Firearm”, the embodiments depicted in  FIGS. 3A and 3C  may be further termed a modern breech design, while the embodiment depicted in  FIG. 3B  may be further termed a straight wall design. Regardless of nomenclature, the gun barrels, depicted by a  10 , have common elements and common purpose, yet variations in meeting that purpose.  
         [0057]     The gun barrels  10  all have a muzzle end  15  at which the projectile (See e.g.  FIGS. 5A-5C ) is both loaded into and from which the projectile ejects from upon the firing of a firearm that the gun barrel  10  is part thereof. The gun barrel  10  include a bore  16  of a first diameter  30 , or caliber. This bore  16  can be of any standard size caliber freely manufactured in the industry. For example, the bore  16  may be a 0.50 caliber, 0.45 caliber, 0.308 caliber, etc. Conversely, the bore  16  certainly can be of any customized, unique diameter. At the distal end of the gun barrel  10  is a breech end  11  having a breech chamber  12  of particular design and configuration. The breech chamber  12  has a second diameter  31 , or caliber. The breech chamber  12  also has breech walls  13  which are adjacent to the cartridge upon its insertion into breech chamber  12 . The breech chamber  12 , similarly, can be configured to match and receive the shape and diameter, of standard size caliber cartridge blanks currently manufactured in the industry. Also, as with the bore  16 , the breech chamber  12  can instead be of a unique, customized shape, configuration and caliber so as to match a custom charge that is placed therein. In either embodiment there is no requirement for an adaptor (not shown) or other additional elements to be located between the outside surface of a cartridge and the breech walls  13 .  
         [0058]     As stated above, the present invention allows for the muzzle end  15  loading of the projectile, while having the charge (e.g., powder within a cartridge casing) be loaded from a breech end  11  of the gun barrel  10 . One way the invention achieves this capability is by configuring the breech end  11  of the gun barrel  10  so that a standard caliber cartridge casing (not shown) with powder, yet no projectile (i.e., “blank” cartridge), may fit therein. In order to prevent the gun user from improperly inserting an entire “traditional” projectile system (i.e., projectile and charge together) in the breech end  11 , the present invention may configure the gun barrel  10  so that the first diameter  30  of the bore  16  is larger in diameter than the second diameter  31  of the breech chamber  12 . In this manner, if the gun user were to inadvertently, for example, to insert the traditional projectile system (i.e., projectile and charge together) into the breech end  11  and into the breech chamber  12  and then fire the firearm, the firearm would harmlessly discharge. This is because the burning powder gases would pass around the ejecting projectile in the gun barrel  10  due to the larger diameter of the bore  16  than the projectile.  
         [0059]     If for example the gun user inserts a traditional 0.308 projectile (i.e., bullet and charge) into the breech end  11  of a gun barrel  10  of the present invention in which the breech chamber  12  is configured to hold a 0.308 charge. That is the diameter of the projectile is approximately a 0.308 caliber diameter. If the user then were to fire the firearm, because the first diameter  30  is larger than the second diameter  31 , although the charge would be activated, the projectile would leave the muzzle end  15  of the gun barrel  10  with little, or no, force and energy. This is because the burning powder gases initially behind and driving the projectile down the bore  16  would quickly pass around the projectile, because the first diameter  30  of the bore  16  is larger than the diameter of the projectile, rendering the projectile with no kinetic energy. This aspect of the invention, therefore, prevents the user from inadvertently attempting to use a traditional projectile system in the gun barrel  10  of the present invention. Thus, the firearm using an embodiment of the gun barrel  10  of the invention, has the added safety benefit of only having successful operation of the firearm by loading a blank charge in the breech chamber  12 , while in consort loading a projectile from the muzzle end  15 .  
         [0060]     The embodiment in  FIG. 3A  includes a connector opening  22  located at the forward end of the breech chamber  12 , before the bore  16 . In this embodiment, the breech chamber  12  has multiple diameters. The connector opening  22  has a third diameter  32 . In this embodiment, the connector opening  22  is a necked down portion of the gun barrel  10  wherein the third diameter  32  is smaller than second diameter  31 . The connector opening  22  portion includes a cant  20  against which the shoulder portion of the cartridge rests against. The cant  20  forms a frusto-conical shaped portion of the breech chamber  12 . This embodiment, for example, could be used with a blank cartridge of standard, shoulder design cartridge. Facing towards the muzzle end  15 , adjacent the connector opening  22  is a stop  19 . The stop  19  provides a surface against which the projectile rests upon the projectile&#39;s insertion into the bore  16 . The stop  19 , thus, allows the projectile to have some purchase against the gun barrel  10 .  
         [0061]     Similarly, the straight wall design depicted in  FIG. 3B , includes a stop  19  against which the projectile rests upon the projectile&#39;s insertion into the bore  16 . The gun barrel  10  in  FIG. 3B  includes a connector opening  22  between the breech chamber  12  and bore  16  or at the forward end of the breech chamber  12 . The connector opening  22  has a third diameter  32 . In this embodiment, the third diameter  32  has a diameter equal to the second diameter  31 . That is, the breech chamber  12  in this embodiment is of uniform diameter.  
         [0062]      FIG. 3C  depicts a third embodiment of a gun barrel  10 . While similar to the embodiment of  FIG. 3A , this embodiment further includes threads  14  on the exterior surface of the breech chamber  12  at the breech end  11  of the gun barrel  10 . The threads  14  provide one type of an attachment means for the gun barrel  10  to the rest of the firearm. Alternatively, the attachment threads  14  may be located on an interior surface of the breech chamber  12 . Note further, the second diameter  31  of the breech chamber  12  in this embodiment is larger in caliber than the first diameter  30  of the bore  16 .  
         [0063]     It should be apparent to one of skill in the art, that other configurations of bore  16 , breech chamber  12 , and connector opening  22  are available. For example, a variation of the embodiment in  FIG. 3A  may alternatively have a first diameter  30  that is equal to, or even greater than, the second diameter  31 . Also, the connector opening  22  could be configured so that the third diameter  32  is the same caliber as the second diameter  31 . Similarly, variations of the embodiment of  FIG. 3B  could include a gun barrel  10  in which the third diameter  22  is smaller than the second diameter  31 . Further, although not explicitly shown, any of the gun barrels  10  of the invention may further employ rifling on the interior surface of the gun barrel  10 .  
         [0064]      FIGS. 4A and 4B  show close-up sectional views of the breech end  11  and breech chamber  12  portion of the gun barrel  10  embodiments depicted in  FIGS. 3A and 3B , respectively. Both embodiments includes a threaded portion  14  at the breech end  11  of the barrel  10 . A chamber insert  17  has matching threads  14  thereby allowing the threading attachment of the chamber insert  17  with the gun barrel  10 . The interior of the chamber insert  17  forms a breech chamber  12  with breech walls  13 . The inclusion of threads  14  on both the exterior surface of the chamber insert  17  and the interior surface of the gun barrel  10  allows for the facile replacement of the chamber insert  17 . Thus, a gun user can readily change chamber inserts  17  for maintenance reasons and/or to change breech chamber  12  configurations (e.g., shapes, diameter(s)  31 ,  32 , connector openings  22 , etc.).  
         [0065]     Turning to a projectile system  40  that is part of the present invention,  FIGS. 5A, 5B , and  5 C depict side sectional views of various embodiments. The various projectile systems  40  includes a charge  45  and a projectile  50 . As discussed supra the projectile  50  is loaded into the gun barrel  10  via the muzzle end  15 , while the charge  45  is loaded into the breech chamber  12  at the breech end  11  of the gun barrel  10 .  
         [0066]     The charge  45  includes a cartridge case  41  in which is explosive powder  42  of suitable composition. Powder  42  that may be employed include smokeless powder, black powder, Pyrodex® powder, pellets, black powder substitutes, or the like, or combinations thereof. The powder  42 , upon its ignition by suitable means ultimately provides the explosive gases which project the projectile  50  out of the gun barrel  10 .  
         [0067]     For purposes of this invention, the term projectile  50  includes a bullet  53  (or de facto projectile) and all appurtenances attached thereto when the bullet  53  are loaded into the muzzle-end  15  of the gun barrel  10 . Attached to the bullet  53  is a sabot  51 . The sabot  51  protects the bullet  52  while it exits the gun barrel  10  and typically falls away harmlessly once the bullet  52  does exit. The sabot  51 , typically made of a suitable, self-lubricating material, such as plastic, helps to make the loading of the bullet  53  into the gun barrel  10  easier. The configuration of the sabot  51  is such that it mates snugly with the bullet  52  and mates suitably with both a sabot mate  43  that is part of the charge  45  and adjoins the stop  19  that is between the breech chamber  12  and bore  16  (See e.g.,  FIGS. 3A and 3B ). The sabot  51 , thus, may have a stop mate surface  52  which is configured to allow the sabot  51  to fit tightly against the stop  19  upon the loading of the projectile  50  into the gun barrel  10 . As depicted in  FIGS. 5A-5C , there are numerous configurations for the projectile system  40 , including the bullet  53 , sabot  51 , and sabot mate  43 .  
         [0068]     For example,  FIG. 5A  shows a sabot mate  43  that is convex in curvature, while the matching sabot  51  is concave in shape. The motion arrow, depicted by a “T”, shows the movement and mating positioning of both the charge  45  and projectile  50  upon the loading of both into the gun barrel  10  from either end. Similarly,  FIG. 5B  shows a different configuration of sabot mate  43  and sabot  51 . This embodiment the sabot  51  includes a male extension, while the sabot mate  42  has a matching female receiving opening. The sabot mate  42  could be a receiving wad. The embodiment shown in  FIG. 5B  could be used with a shot shell or straight-walled cartridge case. Likewise,  FIG. 5C  has a cartridge case  41  with a leading extension that includes a receiving wad  44  that fits within, and matches, the female opening on the sabot  51 .  
         [0069]     It should be further apparent to one skilled in the art, that various calibers of breech chamber  12  and bore  16  may be employed. Matching this, various caliber of cartridge case  41  and projectile  50  can likewise be used. For example, standard diameters  30 ,  31  may be employed for the caliber of breech chamber  12  and bore  16 , respectively. For example, the second diameter  31  may be a 0.45 caliber, while the bore  16  has a 0.50 caliber first diameter  30 . In this manner, standard caliber charges  45  may be used with the present invention, as can standard caliber bullets  53 . The term “standard” means, calibers of charge  45  and bullet  53  that are typically available to the gun using public. Conversely, the present invention may utilize customize caliber and configuration, as well.  
         [0070]      FIG. 6A  depicts a side sectional view of one embodiment of both a gun barrel  10  and the projectile system  40  in use within the gun barrel  10 . In the embodiment shown, the charge  45  may be, for example, in a 0.45 caliber blank cartridge case  41 . The bore  16  in  FIG. 6  is a 0.50 caliber bore. The bullet  53  has been loaded from the muzzle end  15  of the barrel  10  to where the bullet  53  rests against the stop  19  of the chamber insert  17 . The chamber insert  17  is configured to receive the cartridge case  41  which includes the powder  42  and an element  44 . The element  44  may be a powder and compression plug  44  or a powder container plug  44 . In the embodiment shown, the caliber of the chamber  12  is smaller than the caliber of the bore  16 . Note also, that in the embodiment depicted in  FIG. 6  no sabot is used. Additionally, the exterior surface of the cartridge case  41  rests against, or is adjacent to, the chamber insert  17 . Thus, the cartridge case  41  is adjacent to the chamber.  
         [0071]      FIG. 6B  depicts a side sectional view of a second embodiment of both a gun barrel  10  and the projectile system  40  in use within the gun barrel  10 . In the embodiment shown, the gun barrel  10  has no stops  19  on which the bullet  53  partially rests. The bullet  53 , in this embodiment, with s sabot  51 , has been loaded from the muzzle end  15  of the barrel  10  to where the bullet  53  and sabot  51  rest against, and mates with, an element  44  of a cartridge case  41 . The cartridge case  41  which includes the powder  42  and an element  44 . The element  44  may be a powder and compression plug  44  or a powder container plug  44 . In the embodiment shown, the caliber of the chamber  12  is equal to the caliber of the bore  16 . Additionally, the exterior surface of the cartridge case  41  rests on, or adjacent to, the chamber  12 . Thus, the cartridge case  41  is adjacent to the chamber  12 .  
         [0072]      FIG. 7  depicts a perspective view of one embodiment of an entire firearm  1  employing the gun barrel  10  of the present invention. Several pieces of the firearm  1  are standard to the art including a stock  6 , trigger assembly  2 , sights  5 , hammer  3 , and the like. The gun barrel  10  is attached to the rest of the firearm  1 , in this embodiment at a hinge  7 , thereby allowing the user to open, via the hinge  7 , and access the breech end  11  for loading of the charge  45  (see e.g.,  FIGS. 5A, 5B , and  5 C) into the breech chamber  12 . Upon closing of the gun barrel  10 , denoted by motion arrow “M”, the user then may load a projectile  50  in the muzzle end  15  of the gun barrel  10 . Upon the adequate mating of the projectile  50  against the charge  45  (see e.g.,  FIG. 6 ), and proper aiming, safety checks, etc., the user can then activate the firearm  1  via pulling the trigger assembly  2 .  
         [0073]     The foregoing description of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed or to the materials in which the form may be embodied, and many modifications and variations are possible in light of the above teaching. Such modifications and variations that may be apparent to a person skilled in the art are intended to be included within the scope of this invention as defined by the accompanying claims.
The invention relates to a gun barrel in muzzle loading firearm with a breech portion that receives a cartridge case and a muzzle that receives a projectile and an opening that connects both. Also a gun barrel with an opening, or passage bore, that is smaller than the bore of the muzzle end of the firearm is disclosed. A firearm and method of using a firearm with this type of gun barrel is disclosed, as is a projectile system that entails a cartridge with a charge that loads from a breech end and a projectile that loads from the muzzle end of the firearm.