Abstract:
A gas check member, for use in muzzle-loading firearms, frictionally attaches rearward of a sub-caliber bullet to maximize the efficiency of such firearms. The diameter of the gas check preferably exceeds that of the bore slightly to prevent scoring and deformation of the bullet during loading, to hold the projectile in place within the barrel and to prevent moisture from contacting the powder when in place. Upon firing, the gas check minimizes the escape of propellant gases around the projectile and imparts a large, uniformly distributed forward thrust to the bullet to maximize the ballistic qualities of the shot. The gas check preferably incorporates an unstable connection between inner and outer members of the gas check that fractures, at about the time the bullet exits the barrel, to facilitate quick and reliable detachment of the outer member from the bullet. The outer member may also be adapted, preferably by scoring or other weakening of selected regions of the outer member, to itself fracture into multiple pieces, further optimizing detachment or release of a substantial portion of the gas check from the bullet. A more consistent and complete detachment or release helps prevent interference of the gas check with the trajectory of the bullet upon exit from the barrel.

Description:
[0001]     This application is a continuation-in-part of Non-Provisional patent application Ser. No. 10/259,374, filed Sep. 27, 2002, issuing on Jul. 20, 2004 as U.S. Pat. No. 6,763,765, the disclosure of which is incorporated herein by this reference, and claims priority of Provisional Application Ser. No. 60/325,530, filed Sep. 27, 2001, entitled “Break Away Gas-Check for Muzzle Loading Firearms”. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     This invention relates, in general, to the use of muzzle-loading firearms. More specifically, this invention relates to the design and manufacture of projectiles to be used in such firearms.  
         [0004]     2. Related Art  
         [0005]     To function most effectively, muzzle-loading firearms preferably involve the use of a bullet in conjunction with some type of wad or gas check member. Throughout the history of such firearms, various configurations that embrace this design principle have been utilized. The wad or gas check is used to secure the bullet properly within the bore without significant deformation of the bullet, and to prevent the escape of forward thrusting gases around the bullet upon firing the firearm. Prior to the use of wads or gas checks, a malleable lead bullet, with a diameter necessarily greater than that of the bore of the firearm, was ram-rodded down the barrel. In this manner, the bullet was frictionally secured in place over the powder charge and engaged with the rifling of the bore, but was often malformed when being so placed.  
         [0006]     The use of sabots or wrappers was later introduced to facilitate another mechanism of securing the bullet in place. These devices surround a sub-caliber bullet to engage the rifling and secure the bullet without requiring the deformation of a large diameter bullet. When the firearm is discharged, the interaction between wrapper and rifling imparts spin to the bullet. C. T. James and A. Ball have obtained U.S. Pat. Nos. 34,950 and 405,690, respectively, for such wrapper-type devices.  
         [0007]     D. D. Williams, U.S. Pat. No. 35,273, and G.P. Ganster, U.S. Pat. No. 43,017, have acquired patents for inventions in which the wad was directly attached to the bullet for use in muzzle-loading firearms.  
         [0008]     Significant reductions in the efficiency of such firearms often result from destructive interactions between the bullet and bore. When wrappers are used to surround the bullet, the positioning of the wrapper between the bullet and bore may affect the ballistic qualities of the shot. In the case of large-diameter bullets, the scoring and deformation of the projectile that results from the loading process may affect the discharge of the bullet from the bore as well as the in-flight aerodynamics.  
         [0009]     Kearns, U.S. Pat. No. 5,458,064 provides a gas check member for use with sub-caliber bullets, wherein the diameter of the gas check slightly exceeds that of the bore. The gas check is frictionally attached rearward of the bullet and is constructed of deformable, but durable, plastic. However, in cases wherein the gas check member does not detach from the bullet, the velocity and accuracy of the shot may be significantly reduced.  
         [0010]     Therefore, there is a need for a frictionally attached gas check for use in muzzle-loading firearms that is designed to quickly and reliably detach from the bullet upon firing.  
       SUMMARY OF THE INVENTION  
       [0011]     The present invention provides a gas check member for use in muzzle-loading firearms. The gas check member is designed to participate in the loading and firing process such that the loading of such firearms is simple, fast, and effective.  
         [0012]     In addition to serving its gas check function, the invented gas check member is designed to secure the bullet in place within the bore and prevent moisture from contacting the powder once the projectile is secured. All this must be accomplished simply and without interfering with the trajectory of the bullet upon firing.  
         [0013]     The gas check member comprises a generally cylindrical element, with a maximum diameter slightly exceeding that of the bore, which is preferably constructed of a resilient plastic material. The present invention is designed for use with a bullet, and the diameter of the gas check member varies according to the diameter, or caliber, of the bullet and bore. The bullet typically comprises a solid cylindrical, ogive or blunted ogive element that tapers in the direction of its forward end and includes at its back end an engaging means. Such bullets are often constructed of lead or another suitable material with a maximum diameter slightly smaller than the bore. The gas check member is located rearward of the maximum diameter of the bullet where it is frictionally attached by the engaging means. Preferably, the gas check member does not surround the bullet.  
         [0014]     Upon firing, the gas check member prevents rapidly expanding gases, produced by the ignition of the powder, from escaping around the bullet. These gases impart the necessary forward thrust to the projectile; therefore, minimizing the escape of these gases is beneficial to efficient discharge of the bullet from the barrel of the firearm. The gas check member is designed to corral these propellant gases and transmit a distributed force to the projectile that ejects the bullet from the barrel. A substantial portion of the invented gas check detaches from the bullet upon firing to avoid inhibiting the trajectory of the bullet after its exit from the barrel.  
         [0015]     The mechanism of detachment involves the fracture of the gas check member at one or more locations, for example, at its forward end along a connective band or “annular disk” between the engaging member and the outer skirt, and/or at one or more locations on the outer skirt. The gas check is preferably engineered to rupture along at least this annular disk under the force of the gases rushing towards the uncapped distal end of the barrel. The gas check preferably is also engineered to rupture along a plurality of thin, scored, or otherwise weakened axial lines on the outer skirt. Upon exiting the barrel, the skirt of the gas check separates from the bullet, and/or breaks into multiple pieces, allowing the bullet to continue, unimpeded, toward the target. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]      FIG. 1  is a perspective view of the one embodiment of the invented gas check united with a bullet of the preferred design.  
         [0017]      FIG. 2  is a cross-sectional view of the combined projectile of  FIG. 1  demonstrating one basic configuration of the gas check.  
         [0018]      FIG. 2   a  is a cross-sectional view of one possible alternative to the preferred bullet configuration illustrating an exaggerated dove-tail stem.  
         [0019]      FIG. 3  is a bottom view of the gas check of  FIGS. 1 and 2 , showing the position of the thin connective band and the aperture.  
         [0020]      FIG. 4  is a cross-sectional view of the projectile of  FIGS. 1 and 2  in a barrel prior to firing, illustrating the positioning and fit of the gas check within the bore.  
         [0021]      FIG. 5  is a cross-sectional view of the projectile of  FIGS. 1, 2  and  4 , upon exiting the barrel, showing one embodiment of the detachment mechanism of the gas check from the bullet.  
         [0022]      FIG. 6  is a cross-sectional view of another embodiment of the invented gas check, with weakened areas in the gas check skirt.  
         [0023]      FIG. 7  is a cross-sectional view of the a projectile including the gas check of  FIG. 6 , upon exiting the barrel, showing another embodiment of the detachment mechanism of the gas check from the bullet.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0024]     Referring to the Figures, there are shown several, but not the only, embodiments of the invented gas check member. The gas check is designed for use in combination with a bullet, and therefore is drawn in combination with a bullet in  FIGS. 1, 2 ,  4 ,  5 , and  7 . The combination of a gas check member with a bullet will herein be referred to as a projectile.  
         [0025]     In  FIGS. 1-5 , gas check member  10  comprises a generally cylindrical element preferably constructed of a resilient plastic material and engineered to attach rearward of the maximum diameter of the bullet  20 , as shown in  FIGS. 1 and 2 . The maximum diameter of the bullet is preferably slightly less than that of the bore, and the diameter of the gas check member exceeds that of both bullet and bore  50 . This relationship is illustrated in  FIG. 4 . Bullets used in muzzle-loading firearms are typically composed of a suitable solid, but deformable, material such as lead, and exhibit a tapered cylindrical, ogive or blunted ogive design. The preferred bullet for use with the invented gas check includes a short stem  21  protruding backward along the central axis of the bullet that provides a point of attachment for the gas check member. One alternative embodiment, for a more secure attachment, may provide a dove-tailed stem in which the diameter d at its proximal end is slightly smaller than the diameter D at its distal end, as shown in  FIG. 2   a.  Still another alternative may provide a bullet with a small circular cavity depressed in its back end along the central axis for receiving an oversized stem-like engaging member protruding from the gas check.  
         [0026]     The forward portion of the gas check member preferably includes an engaging member lying substantially within an outer wall, wherein the outer wall substantially resembles a skirt, as shown in  FIG. 2 . In the preferred embodiment, the engaging member comprises an inner ring  13  with a small aperture  30 . The inner ring is connected to the skirt  12  by a connecting element. Preferably, this connecting element is a band  14  of plastic material which is substantially reduced in thickness relative to the engaging inner ring  13 , as shown in  FIGS. 2 and 3 . The thickness t of the connecting element is preferably between ⅛ and ½ that of the thickness T of the engaging member, as shown in  FIG. 2 . Several alternatives to the thin connecting band  14  of the preferred embodiment are foreseeable so long as the skirt separates from the engaging member upon exit from the barrel. For example, the connecting element may comprise a band of material that has been significantly weakened by exposure to light, heat, mechanical, or other stress. In the preferred embodiment, the thickness of the inner ring  13  is greater than that of the band  14  to provide strength and additional surface area for contacting the bullet stem  21 , and the diameter of the aperture is slightly smaller than the largest diameter of the bullet stem.  
         [0027]      FIG. 2  demonstrates the preferred mechanism of attachment between bullet  20  and gas check  10 . When the stem  21  is inserted into the aperture  30 , the resilient material of the inner ring  13  tolerates a slight enlargement of the aperture to permit a secure frictional attachment of bullet and gas check. One foreseeable alternative to this mechanism of attachment may comprise a slightly oversized, deformable plastic stem protruding from the forward end of the engaging member which is received within a depression in the back of the bullet. In this case, the engaging stem will be compressed slightly to frictionally secure the gas check to the bullet. Other alternative means are also possible.  
         [0028]     The attachment between bullet and gas check remains intact until exiting the barrel for the following reasons: to engage the rifling of the bore, to prevent moisture leakage from the barrel  51  onto the powder after the projectile  1  is in place and generally center the bullet in the bore to prevent interference between bullet and bore  50  while loading. The usual positioning of the projectile  1  within the bore is shown in  FIG. 4 .  
         [0029]     Upon firing, the ignition of the powder, and subsequent production of propellant gases, facilitates the separation of the bullet from the gas check member. In the embodiment of  FIGS. 1-5 , the separation begins at the thin connecting element between the engaging member and the outer member. As shown in  FIGS. 2 and 4 , an unstable gap  11  in the preferred embodiment is created as a result of the minimal attachment between the inner ring  13  and outer skirt  12  of the gas check member. When the firearm is fired, the rapidly expanding gases propel the projectile  1  forward. The configuration of the gas check  10  allows it to deliver a uniformly distributed force to the bullet to eject it from the barrel, but the thin plastic band  14  is unable to withstand the force of the escaping gases as they rush into the weakened zone  11 . The thin band  14  then breaks apart and the outer skirt  12  shatters and/or separates from the inner ring  13  and exits the barrel  51 , as shown in  FIG. 5 . After exit from the barrel, shattered fragments of the skirt will travel at a significantly reduced rate of speed relative to the bullet. Therefore, it is expected that such pieces will not disturb the flight of the bullet. The inner ring remains attached rearward of the bullet on its path to the target while the skirt and/or its fragments fall to the ground. The small diameter and light weight of the inner ring allow it to remain attached to the bullet without compromising the ballistic integrity of the bullet.  
         [0030]     In operation, the simplicity of the invented gas check enables users of muzzle-loading firearms to load such weapons quickly and easily. In addition, the gas check improves the ballistic qualities of the shot by minimizing both the escape of essential propellant gases and harmful bullet and bore interactions. Ultimately, the gas check improves the accuracy and effectiveness of muzzle-loading firearms.  
         [0031]     The gas check may be adapted to break at locations other than the thin or weakened connecting element between the engaging member and the outer shirt. For example, as discussed above, the outer skirt may shatter into multiple fragments. In some embodiments of the invented gas check, the outer skirt may be adapted to break apart into multiple fragments at pre-determined scored, thinned, perforated, or otherwise weakened locations, preferably in addition to the outer skirt breaking from the engaging member at the connecting element. Alternatively, but less preferably, the outer skirt may be adapted to break apart at these other locations without the connecting element breaking.  
         [0032]     In the embodiment of  FIGS. 6 and 7 , the gas check  110  comprises both a thin band  114  and a plurality of weakened regions  130  running axially along the outer skirt  112 . The weakened regions  130  extend from at or near the rear edge  122  to a location at or near the band  114  near the front  132  of the gas check. The weakened regions  130  may comprise various systems for weakening the outer skirt at those locations, including molding/forming the outer skirt to be thinner, scoring the skirt wall, and/or otherwise perforating or thinning the skirt wall, at those locations.  
         [0033]     Preferably, as discussed above for the embodiment of  FIGS. 1-5 , the outer surface  140  of the skirt  112  is generally cylindrical, with a maximum diameter slightly exceeding that of the bore, and the gas check  110  is preferably constructed of a resilient plastic material. The inner surface may, however, be recessed at the weakened regions  130 , making the skirt wall thin along the weakened region axial lines, and therefore, more likely to break than the surrounding outer skirt wall. Alternatively, the skirt wall may be made thin in the weakened regions  130  by recessing portions of the outer surface  140 , as long as this does not interfere significantly with the preferably gas check performance, including: generally centering the bullet in the bore to prevent interference between bullet and bore while loading, preventing moisture leakage from the barrel onto the powder after the projectile is in place, preventing the escape of forward thrusting gases around the bullet upon firing the firearm, and engaging the rifling of the bore. Alternatively, or in addition, the skirt wall may be scored along the axial lines, to weaken the wall and make it more likely to break than the surrounding wall.  
         [0034]     Upon firing, the projectile  101  comprising the bullet  20  and the gas check  110 , travels through the rifle barrel, with the gas check performing its function similarly to the embodiment of  FIGS. 1-5 . When the firearm is fired, the rapidly expanding gases propel the projectile  101  forward. The configuration of the gas check  110  allows it to deliver a uniformly distributed force to the bullet to eject it from the barrel, but the thin plastic band  114  and the weakened regions  130  are unable to withstand the force of the escaping gases as they rush into the interior space  111  of the gas check. The thin band  114  then breaks apart and the outer skirt  112  breaks at the weakened regions  130 , and the resulting gas check pieces, which are in effect fragments  160  of the skirt, separate from the thin band  114  or the inner ring  113  and exit the barrel  51 , as shown in  FIG. 7 . After exit from the barrel, the fragments  160  of the skirt will travel at a significantly reduced rate of speed relative to the bullet. Therefore, it is expected that such pieces will not disturb the flight of the bullet. The inner ring  113  remains attached rearward of the bullet on its path to the target while the fragments  160  fall to the ground. The small diameter and light weight of the inner ring allow it to remain attached to the bullet without compromising the ballistic integrity of the bullet.  
         [0035]     Thus, the minimal attachment between the inner ring  113  and outer skirt  112  of the gas check member, plus the weakened skirt  112 , result in substantial disintegration or breakage of the gas check at about the time the projectile leaves the barrel. Preferably, the weakened regions  130  create multiple clean breaks, resulting in generally equal pieces of the outer skirt breaking off of the engaging member and resulting in all or substantially all of the outer skirt breaking off of the projectile. The inventor believes that the breakage of the gas check at both the band  114  and at the weakened regions  130  results in more uniform gas check performance (especially in terms of a more consistent release of the gas check from the bullet) and in improved accuracy to the bullet. This more consistent breaking away of the gas check helps prevent the gas check from affecting the bullet&#39;s accuracy and adversely affecting the bullet&#39;s accuracy, as it increases the probability that only the inner ring  113 , and no unequally-size remnants of the skirt, will remain on the bullet. Though less preferred, other breakage patterns and non-equal fragments may also result from firing the weapon and may still be within the scope of the invention.  
         [0036]     Therefore, many embodiments of the invention may be described as an annular gas check for use in muzzle-loading firearms, wherein the gas check comprises an outer wall with diameter exceeding that of the bore of the firearm, and an engaging member for attaching the gas check to the back of a bullet, wherein the engaging member is joined to the outer wall by an appreciably thin, or weakened, connecting element. At about the time of exit from the barrel of said firearm, said outer wall and said engaging member may become separated in the region of the thin connecting element. Instead or preferably in addition, many embodiments may comprise said outer wall being adapted to break into a plurality of pieces upon or near in time to the projectile exiting the barrel.  
         [0037]     Embodiments may includes the outer wall engaging the rifling of the bore to hold the bullet in place within the barrel, to prevent moisture from the barrel from contacting the powder when in place within the barrel, and to impart spin to the bullet upon firing. Other embodiments may include the gas check frictionally attaching to the back of said bullet by said engaging member. The gas check may harness rapidly expanding gas products of gunpowder ignition to impart a distributed forward thrust to said bullet, and, under the thrusting force of said gases, the connecting element may break apart upon exit from the barrel thereby separating said engaging member and outer wall to prevent interference with the ballistic properties of said bullet. Instead or preferably in addition, the rapidly expanding gas thrusting forces cause the outer wall to break into a plurality of pieces, preferably at weakened regions in the outer wall.  
         [0038]     Other embodiments may be a gas check comprising an outer wall with diameter exceeding that of the bore of the firearm, and an engaging mechanism substantially surrounded by said outer wall for frictionally attaching to the rearward portion of a bullet, wherein the engaging mechanism is connected to the outer wall by a band of material which is appreciably weakened or reduced in thickness relative to the thickness of the engaging mechanism such that upon exit from the barrel said band of material fractures thereby separating said outer wall from said engaging mechanism. Instead or preferably in addition, the outer wall, at about the time of exit from the barrel, breaks into a plurality of pieces, preferably at weakened regions in the outer wall.  
         [0039]     Other embodiments may be an annular gas check comprising a generally cylindrical outer skirt with diameter slightly exceeding that of the bore of the firearm, and an inner ring for frictionally attaching said gas check to a bullet or similar projectile wherein the ring is coaxial with and substantially surrounded by said outer skirt. The ring may feature an aperture for receiving a short stem protruding from the rear of the bullet along its central axis; and the ring may be connected to the outer skirt at its forward end by a band of material which is appreciably weakened or reduced in thickness relative to the thickness of the inner ring, such that upon exit from the barrel said band of material fractures thereby separating said outer skirt from said inner ring. The gas check may include the aperture in said inner ring having a diameter slightly smaller than the largest diameter of said bullet stem, and said aperture may tolerate a slight deformation to receive said stem thereby frictionally attaching the gas check to the back of said bullet. The gas check may harness rapidly expanding gas products of gunpowder ignition to impart a distributed forward thrust to said bullet, wherein under the thrusting force of said gases said band of material breaks apart upon exit from the barrel, thereby separating said inner ring and outer skirt to prevent interference with the ballistic properties of said bullet. Instead or preferably in addition, the rapidly expanding gas thrusting forces cause the outer wall to break into a plurality of pieces, preferably at weakened regions in the outer wall.  
         [0040]     Other embodiments of the invention may also be made and used after one of skill in the art reads this disclosure and views the drawings. Although this invention has been described above with reference to particular means, materials and embodiments, it is to be understood that the invention is not limited to these disclosed particulars, but extends instead to all equivalents within the scope of the following claims.