Abstract:
The present invention relates to systems and methods for using a cartridge case as a tool to install or remove firearm accessories such as a barrel attachment. The barrel attachment includes a coupling section for attaching the barrel attachment to a firearm barrel. The barrel attachment also includes a rim channel for engaging a portion of the rim of a cartridge case. This rim channel provides mechanical leverage by enabling a user to apply force on the engaged cartridge case to rotate the barrel attachment around a bore axis of the firearm barrel. In some embodiments, the rim channel is an integral portion of a cartridge rim slot machined into the exterior part of the barrel attachment. Ideally, the rim channel includes a curved portion to increase the load-bearing contact area. The rim channel can also be adapted to accept different case rim sizes. Multiple rim slots can be machined into the barrel attachment, allowing the user to spread out the forces amongst multiple cartridge cases. The contact area between the rim of the cartridge case and the barrel attachment can be further increased by sliding a half-moon insert into the rim slot.

Description:
BACKGROUND 
       [0001]    The present invention relates to systems and methods for using a firearm cartridge as a field tool to attach or detach firearm accessories, thereby eliminating the need for carrying a specialized tool such as a wrench. 
         [0002]    Accessories for firearms have increased steadily over time in both functionality and flexibility, and today, there are many firearm accessories available including optics and barrel-mounted accessories such as muzzle brakes and flash suppressors. Many barrel-mounted accessories are attached to the barrel muzzle using screw threads or some other mechanical coupling system. Because all modern firearms are rifled for accuracy, whenever a firearm is fired, rotation impulse forces are generated and these forces have a tendency to tighten threaded muzzle accessories relative to the barrel. In addition, carbonization in muzzle accessories is inevitable from repeated exposure to hot gaseous propellant byproducts and over time such carbon deposits tend to “gum-up” attachment areas of these muzzle accessories. 
         [0003]    To ensure proper reliable functioning, field maintenance of firearms have to be performed regularly. This involves field stripping and cleaning dirty components including muzzle accessories. Further, in the field, a user may decide to make reconfigure his/her firearm such as changing muzzle accessories, when the services of a gunsmith and/or gunsmithing tools are not available. 
         [0004]    It is therefore apparent that an urgent need exists for systems and methods of using easily accessible and adaptable “tools”, such as firearm cartridge cases, to maintain and reconfigure firearms in the field. Such improved equipment and techniques will enable a user to perform field maintenance and reconfiguration of his/her firearm without having to carry an extensive tool kit. 
       SUMMARY 
       [0005]    To achieve the foregoing and in accordance with the present invention, systems and methods for using a cartridge case as a tool to install or remove firearm accessories such as barrel attachments. 
         [0006]    In one embodiment, a barrel attachment includes a coupling section for attaching the barrel attachment to a firearm barrel. The barrel attachment also includes a rim channel for engaging a portion of the rim of a cartridge case. This rim channel provides mechanical leverage by enabling a user to apply force on the engaged cartridge case to rotate the barrel attachment around a bore axis of the firearm barrel, for the purpose of attaching or removing the barrel attachment. 
         [0007]    In some embodiments, the rim channel is an integral portion of a cartridge rim slot machined into the exterior part of the barrel attachment, and the rim slot is substantially parallel to the bore axis. Ideally, the rim channel includes a curved portion corresponding to the radius of the cartridge rim to increase the load-bearing contact area whenever the rotation forces are applied to the cartridge case by the user. The rim channel can also be adapted to accept different case rim sizes. 
         [0008]    In some embodiments, multiple rim slots are machined into the exterior of barrel attachment, allowing the user to spread out the forces amongst multiple cartridge cases. For example, two rim slots, located 180 degrees from each other, will allow the user to rotate the barrel attachment in a manner similar to using a T-handled wrench. 
         [0009]    It is also possible to slide a half-moon insert into the rim slot thereby increasing the contact area between the rim of the cartridge case and the barrel attachment, and reducing the risk of deforming the cartridge rim. This half-moon insert can be further configured to provide impact forces to, for example, enable a police officer to break an automobile window during a hostage rescue mission. 
         [0010]    Note that the various features of the present invention described above may be practiced alone or in combination. These and other features of the present invention will be described in more detail below in the detailed description of the invention and in conjunction with the following figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    In order that the present invention may be more clearly ascertained, some embodiments will now be described, by way of example, with reference to the accompanying drawings, in which: 
           [0012]      FIG. 1A  is an isometric view of a barrel attachment with a rim channel configured to accept the rim of a firearm cartridge case, in accordance with one embodiment of the present invention; 
           [0013]      FIG. 1B  is an enlarged view of the front portion of the embodiment of  FIG. 1A  showing the rim channel in greater detail together with hidden lines; 
           [0014]      FIGS. 1C and 1D  are bottom and side views of the embodiment of  FIG. 1 ; 
           [0015]      FIG. 1E  is a front view showing an exemplary cartridge coupled to the embodiment of  FIG. 1A ; 
           [0016]      FIG. 2  shows another embodiment of the present invention configured to accept multiple cartridge sizes; 
           [0017]      FIGS. 3A-B  and  FIGS. 3C-D  are respective bottom and front views illustrating two additional embodiments configured to accept multiple cartridge sizes; 
           [0018]      FIGS. 4A ,  4 B and  4 C are isometric, bottom and front views of a half-moon insert to increase the contact area between the rim of the cartridge case and the barrel attachment; 
           [0019]      FIGS. 5A and 5B  are bottom views of two additional exemplary embodiments of barrel attachments in accordance with the present invention; 
           [0020]      FIG. 6  is a front view of yet another embodiment of the present invention configured to accept multiple cartridge cases; 
           [0021]      FIGS. 7 and 8  are isometric views of a multi-prong flash suppressor and a bird-cage flash suppressor, respectively, both configured to accept the rim of a cartridge case; 
           [0022]      FIG. 9  is a bottom view of another exemplary half-moon insert configured to increase the contact area between the rim of the cartridge case and the barrel attachment, and further configured to provide impact force; and 
           [0023]      FIGS. 10A and 10B  are top and front views of yet another half moon insert configured to increase the contact area between the rim of the cartridge case and the barrel attachment, and further configured to provide a rim slot for accepting an additional cartridge with smaller rim size. 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    The present invention will now be described in detail with reference to several embodiments thereof as illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. It will be apparent, however, to one skilled in the art, that embodiments may be practiced without some or all of these specific details. In other instances, well known process steps and/or structures have not been described in detail in order to not unnecessarily obscure the present invention. The features and advantages of embodiments may be better understood with reference to the drawings and discussions that follow. 
         [0025]    The present invention relates to systems and methods for using a cartridge case to provide additional mechanical leverage for installing or removing a barrel attachment from a firearm barrel without the need for a specialized tool. To facilitate discussion,  FIG. 1A  shows an isometric view of a barrel attachment  100  in accordance with one embodiment of the present invention. Barrel attachment  100  includes an attachment body  160  and a coupling section  190  for securing the attachment  100  to a firearm barrel (not shown). In this example, attachment  100  functions as a muzzle brake with gas ports  162 ,  164  and  166 . Barrel attachment  100  includes a case rim slot  110  having substantially parallel rim channel sections  122 ,  124  configured to accept the rim of a firearm cartridge case (not shown). 
         [0026]      FIG. 1B  is an enlarged view of the front portion of barrel attachment  100  showing rim slot  110  in greater detail together with hidden lines showing a curved rim channel section  126  adjacent to both rim channel sections  122 ,  124 . To additional clarity for rim slot  110 ,  FIGS. 1C and 1D  provide bottom and side views of barrel attachment  100 . 
         [0027]    Referring now to  FIG. 1E , a front view of barrel attachment  100 , a case rim  188  of an exemplary firearm cartridge  180  is inserted into rim slot  110 , providing a user with mechanical leverage for rotating barrel attachment  100  substantially around the bore axis of a firearm barrel. The mechanical leverage enables the user to secure attachment  100  to a firearm barrel, or conversely, to remove attachment  100  from the firearm barrel without the need for an addition tool, such as a wrench. This ability to couple and decouple barrel attachments in the field without having to carry a specialized tool is highly advantageous for both field maintenance and reconfiguration, since live cartridges and/or fired cartridge cases are almost always available to the user. Conversely, during dry practice sessions, for safety reasons, often, only blank and/or inert cartridges are made available to the user. 
         [0028]      FIG. 2  is a bottom view of another embodiment, barrel attachment  200 , with a multi-caliber rim slot  210  having rim channel sections  222 ,  224  substantially tapering towards a curved rim section  226 , thereby enabling rim slot  210  to accept two or more cartridge rim sizes. This flexibility is especially advantageous amongst groups of users with different caliber firearms. For example, a group of sport shooting competitors may have a mixture of small and large caliber rifles. Similarly, law enforcement field teams in the U.S.A. are typically multi-caliber with 5.56×45 mm caliber select-fire carbines issued to most team members and the larger 7.62 mm caliber precision rifles issued to a couple of marksmen. 
         [0029]    Accordingly, when equipped with barrel attachment  200 , a user issued with a smaller 5.56 mm caliber firearm has the option to use a teammate&#39;s larger and longer  7 . 62  caliber cartridge capable of providing greater mechanical leverage for rotating barrel attachment  100 . In this example, with such a flexible multi-caliber rim slot  210 , it may also be possible to use cartridges with larger rims, associated with long-range firearms, team-operated firearms, and/or vehicle-mounted firearms, such as a 7.62×67 mm (0.300 Win Mag) caliber cartridge, a 8.58×70 mm (0.338 Lapua Mag) caliber cartridge, and/or a 12.7×99 mm (0.50 BMG) caliber cartridge. 
         [0030]      FIGS. 3A and 3B  are the bottom and front views illustrating an additional embodiment, barrel attachment  300 A, configured to accept dual cartridge rim sizes. Barrel attachment  300 A includes a narrower caliber rim slot, having a curved rim channel section  326   a  adjacent to rim channel sections  322   a ,  324   a , configured to accept a cartridge (not shown) with a smaller rim. Attachment  300 A also includes a wider caliber recessed rim slot  340   a , having a curved rim channel section  346   a  adjacent to rim channel sections  342   a ,  344   a , configured to accept a cartridge (not shown) with a larger rim. 
         [0031]      FIGS. 3C and 3D  are the bottom and front views illustrating yet another embodiment, barrel attachment  300 C, configured to accept dual cartridge rim sizes. Barrel attachment  300 C includes a dual cartridge rim slot  340   c , having a curved rim channel section  326   c  adjacent to rim channel sections  322   c ,  324   c , configured to accept a cartridge (not shown) with a smaller rim. Dual cartridge rim slot  340   c  also includes a rim channel section  342   c  and an opposing rim channel section  344   c , configured to accept a cartridge (not shown) with a larger rim. 
         [0032]    Although exemplary barrel attachments  300 A and  300 C are each configured to accept two cartridge rim sizes, it is contemplated that barrel attachments can be configured to accept, for example, a three or more cartridge rim sizes. It is also contemplated that barrel attachments with multiple rim capability, e.g., attachments  200 ,  300 A and  300 C, can be configured to accept a wide variety of cartridge case designs incorporating a rim, including “rimmed” (protruding rim) cartridges, “rimless” (recessed or non-protruding rim) cartridges, straight-wall cartridges, and/or tapered cartridges such as bottle-neck cartridges. 
         [0033]      FIGS. 4A ,  4 B and  4 C are an isometric view, a bottom view and a front view, respectively, of a half-moon insert  400  configured to further increase the contact area between the rim of a cartridge case and a corresponding barrel attachment (not shown in  FIGS. 4A-4C ), thereby minimizing the risk of deformation of the cartridge rim, since firearms cartridge cases are typically manufactured using a malleable alloy such as brass. Insert  400  comprises a stacked pair of half-moon sections  460 ,  480 . 
         [0034]    Referring also to  FIGS. 1B and 1E , insert  400  is useful in combination with, for example, barrel attachment  100  and cartridge case  180 . Larger-diameter half-moon section  460  is configured to slide into rim slot  110 , after cartridge case  180  has been inserted. The larger-diameter half-moon section  460  stabilizes the rim  188  of cartridge case  180  against curved rim channel section  126 , while the smaller-diameter half-moon section  480  provides additional load-bearing contact area opposite of curved rim channel section  126 . 
         [0035]    In some embodiments, half-moon insert  400  can be secured to a corresponding barrel attachment using a variety of mechanical devices (not shown) such as a spring-loaded ball-detent or a set screw. Insert  400  also serves to protect the rim slot of the barrel attachment from damage. 
         [0036]      FIGS. 5A and 5B  are bottom views of two additional exemplary barrel attachments  500 A and  500 B. Attachment  500 A includes a blind rim slot having a curved entry recess  528  for inserting the rim of a cartridge (not shown). Curved entry recess  528  is adjacent to rim channel sections  522 ,  524 . An additional curved rim channel section  526 , adjacent to both rim channel sections  522 ,  524 , provides increased contact area between barrel attachment  500 A and the rim of the cartridge. 
         [0037]    Similarly, attachment  500 B includes a blind rim slot having a curved entry recess  588  adjacent to rim channel sections  582 ,  584 . A curved rim channel section  586 , adjacent to both rim channel sections  582 ,  584 , provides additional contact area between barrel attachment  500 B and the rim of a cartridge case (not shown). 
         [0038]    Referring now to  FIG. 6 , a front view of yet another embodiment, barrel attachment  610  includes rim slots  612 ,  714  configured to accept cartridge cases  632 ,  622 , respectively, at two separate radial locations, 12 o&#39;clock and 6 o&#39;clock, relative to the bore of the barrel. In this example, cartridge cases  622 ,  632  enable attachment  610  to function in a manner similar to that of a T-handled wrench, thereby doubling the mechanical leverage available when compared with a barrel attachment configured to accept a single similarly sized cartridge case. Note that the various disclosed embodiments, including barrel attachment  610 , can be further configured to include additional rim slots (not shown) to accept three or more cartridge cases, at multiple radial locations distributed around the bore axis of the barrel, for example, at 12 o&#39;clock, 3 o&#39;clock, 6 o&#39;clock and 9 o&#39;clock. It is also contemplated that barrel attachments with multiple cartridge capability, e.g., attachment  610 , can be configured to accept multiple cartridges with similar and/or different case rim designs and/or rim sizes. 
         [0039]      FIG. 7  is an isometric view of a multi-prong flash suppressor  700  (also commonly referred to as a flash hider) configured to accept the rim of a cartridge case (not shown). In this embodiment, the U-shaped cutout  710  between two adjacent suppressor prongs includes a curved rim channel section  726 , and adjacent rim channel sections  722  and  724 . Since carbonized deposits on suppressor  700  are expected from repeated firing, the dimensional tolerances of rim cutout  710  and channel width/depth of rim channel sections  722 ,  724 ,  726  should be appropriately relaxed. 
         [0040]      FIG. 8  is an isometric view of a bird-cage flash suppressor  800  configured to accept the rim of a cartridge case (not shown). In this embodiment, one of the through-slots of bird case suppressor  800  includes a curved ledge  810  for supporting and guiding the rim of the cartridge case during insertion. Curved ledge  810  is adjacent to rim channel sections  822 ,  824 . In addition, a curved rim channel section  826 , adjacent to both rim channel sections  822 ,  824 , provides additional contact area between flash suppressor  800  and the rim of the cartridge case. Tolerances of curved ledge  810 , and rim channels  822 ,  824 ,  826  should also be appropriately relaxed because of potential exposure to carbonized deposits. 
         [0041]      FIG. 9  is a bottom view of yet another embodiment, half-moon insert  900 , configured to further increase the contact area between the rim of a cartridge case and the rim slot of a corresponding barrel attachment (not shown) in a manner similar to that of insert  400  described above, via a stacked pair of half-moon sections  960 ,  980 . In this example, insert  900  also includes one or more impact points, e.g., points  942 ,  944 , configured to provide focused impact forces capable of shattering glass targets, such as an automobile window. Insert  900  can be secured to a corresponding barrel attachment using a mechanical device  970 , such as a spring-loaded ball-detent or a set screw. Such an impact force capability can be very useful for law enforcement applications. 
         [0042]    Referring now to  FIGS. 10A and 10B , top and front views of yet another embodiment, half-moon insert  1000  is configured to increase the contact area between the rim of a cartridge case and a corresponding barrel attachment (not shown) in a manner similar to that of insert  400  described above. Insert  1000  further includes a rim slot  1010  with rim channel sections  1022 ,  1024  configured to accept a different cartridge with smaller rim size. Such an insert  1000  are especially useful for users with multiple firearms, such as a park warden, who may be issued with both a rifle and a sidearm such as 9×19 mm caliber pistol. For example, during a shift, a warden may elect to use the smaller pistol cartridge for better control and also perhaps to avoid any risk of rim deformation of a limited supply of the rifle ammunition. 
         [0043]    Numerous other applications of the present invention are also possible. For example, while the exemplary embodiments of barrel attachments described include mainly muzzle brakes and flash suppressors, it is intended that the disclosed concepts of using a cartridge rim as a field tool are also applicable to compensators, barrel harmonic stabilizers such as harmonic dampeners and balancers, barrel-coupling protectors such as thread protectors and quick-detach coupling protectors, sound suppressors, projectile-launching attachments such as flare, smoke and flash-bang launchers, blank-firing attachments, sighting attachments such as laser sights, and also any combinations thereof. 
         [0044]    In addition, the rim slots disclosed above can be adapted to accept other firearm accessories such as picatinny rails, bayonet mounts, flashlight mounts, and barrel supports such as bipods and monopods. A specialized steel tool with a variety of changeable cartridge rim ends can also be issued as part of a gunsmith&#39;s tool kit. 
         [0045]    In sum, the present invention provides systems and methods for using firearm cartridge cases to provide additional mechanical leverage for installing or removing barrel attachments without the need for specialized tools. These exemplary systems and methods disclosed are intended to be practiced alone or in combination. 
         [0046]    While this invention has been described in terms of several embodiments, there are alterations, modifications, permutations, and substitute equivalents, which fall within the scope of this invention. It should also be noted that there are many alternative ways of implementing the methods and apparatuses of the present invention. It is therefore intended that the following appended claims be interpreted as including all such alterations, modifications, permutations, and substitute equivalents as fall within the true spirit and scope of the present invention.