Abstract:
The firearm magazine capacity limiter selectively limits the capacity of the magazine to comply with applicable laws or regulations. The capacity limiter has a rod including a follower contact end and an opposite attachment end that secures removably in a passage provided through a closure plate at one end of the magazine. The rod may have any length desired to limit the maximum capacity of the magazine as desired. Various attachment configurations are provided, including threaded attachment, quarter turn attachment, and sliding attachment via a capture flange on the attachment end of the rod. The capacity limiter may be used with detachable box-type magazines where the closure plate is the floor plate of the magazine, or with tubular magazines where the closure plate is the forward plug at the end of the magazine.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/044,951, filed Sep. 2, 2014. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to ammunition magazines for multiple shot firearms, and particularly to a firearm magazine capacity limiter enabling the user to set or limit the maximum number of rounds or cartridges to be carried in the magazine. 
         [0004]    2. Description of the Related Art 
         [0005]    Most sporting firearms and handguns are capable of firing multiple shots before reloading if equipped with a magazine holding at least a few rounds of ammunition. This is true of semiautomatic hunting rifles, pump and semiautomatic shotguns, and many handguns. Detachable box-type magazines are generally capable of holding a relatively large number of rounds of ammunition, e.g., ten to thirty rounds in the case of many rifles. Even larger capacity magazines are available for many firearms. Even shotguns having tubular magazines are typically capable of holding perhaps five shells, more or less, depending upon the gun, if the magazine can receive its full capacity. 
         [0006]    However, many jurisdictions and controlling bodies have laws or regulations controlling or limiting the number of shots that may be fired from a firearm before reloading. This may be due to hunting or game conservation laws or regulations, firearm protection laws, or for other reasons. While these various laws and regulations are generally consistent with one another, there can be some variation from state to state, region to region within a state, and even from season to season, and may be dependent upon the specific type of game being hunted. A firearm owner or user may have a firearm with a magazine capacity that is permissible under a given set of regulations or laws, but that may exceed the permissible capacity in other circumstances or areas, e.g., when traveling to a different state or area for hunting, or when hunting a different species of game. 
         [0007]    Thus, a firearm magazine capacity limiter solving the aforementioned problems is desired. 
       SUMMARY OF THE INVENTION 
       [0008]    The firearm magazine capacity limiter comprises a rigid rod that is installed through a modified floor plate of a detachable box-type magazine, or through the forward cap of a tubular magazine. In the case of box-type magazines, the rod extends through the follower spring in the magazine to limit the travel of the follower, and thus limit the amount of ammunition that may be loaded into the magazine above the follower. In the case of tubular magazines, the rod extends generally axially through the tube to limit the number of shells that may be loaded into the tube. 
         [0009]    A number of different attachment means may be used to secure the capacity limiter in the magazine. One embodiment provides a thickened boss having an internally threaded passage. The boss is installed in the floor plate of a box-type magazine or in the forward cap of a tubular magazine. The capacity limiter comprises a rigid rod with a follower contact end and an opposite magazine attachment end having an externally threaded portion that threads into the internally threaded boss of the magazine. Alternatively, the floor plate passage may be threaded and the thickened boss eliminated, if the plate is sufficiently thick to provide sufficient mounting strength for attachment of the rod, 
         [0010]    Another embodiment has a keyhole-shaped flange that fits through a congruent passage in the floor plate or cap of the magazine. The flange has an extension that captures the edge of the passage of the magazine when turned through a partial revolution. Still another embodiment utilizes the keyhole-shaped passage, but provides a circular flange at the attachment end of the rod. The circular flange passes through the larger portion of the keyhole-shaped passage and slides laterally to capture the edge of the narrower extension of the keyhole-shaped passage between the circular flange and the outer portion of the attachment end of the rod. 
         [0011]    Any of the above-described embodiments may be provided with capacity limiting rods of any desired length in order to limit the magazine capacity as needed or required by applicable laws and/or regulations. 
         [0012]    These and other features of the present invention will become readily apparent upon further review of the following specification and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is an exploded perspective view of a firearm magazine capacity limiter according to the present invention, the wall of the box-type magazine being broken away and partially in section to show internal details of the magazine, the capacity limiter rod being removed therefrom. 
           [0014]      FIG. 2  is a perspective view of the firearm magazine capacity limiter of  FIG. 1  with the wall of the box-type magazine being broken away and partially in section to show internal details of the magazine, but showing the rod of the capacity limiter installed in the magazine. 
           [0015]      FIG. 3A  is an exploded elevation view of a long rod embodiment of a firearm magazine capacity limiter according to the present invention, showing the rod of the capacity limiter separated from a detachable box-type magazine. 
           [0016]      FIG. 3B  is an exploded elevation view of a medium-length rod embodiment of a firearm magazine capacity limiter according to the present invention, showing the capacity limiter separated from a detachable box-type magazine. 
           [0017]      FIG. 3C  is an exploded elevation view of a short rod embodiment of a firearm magazine capacity limiter according to the present invention, showing the capacity limiter separated from a detachable box-type magazine. 
           [0018]      FIG. 4A  is an exploded partial perspective view of an alternative embodiment of a firearm magazine capacity limiter according to the present invention, showing a detachable box-type magazine broken away and partially in section, the attachment end of the rod having a keyhole-shaped flange and the floor plate of the magazine having a mating keyhole-shaped passage. 
           [0019]      FIG. 4B  is an exploded partial perspective view of another alternative embodiment of a firearm magazine capacity limiter according to the present invention, showing a detachable box-type magazine broken away and partially in section, the attachment end of the rod having a circular flange and the floor plate of the magazine having a cooperating passage for a sliding fit of the rod attachment end therein. 
           [0020]      FIG. 5A  is an exploded partial perspective view of another alternative embodiment of a firearm magazine capacity limiter according to the present invention, showing with the muzzle end of a firearm having a tubular magazine, illustrating the installation of the magazine capacity limiter through the magazine closure cap of the firearm. 
           [0021]      FIG. 5B  is an exploded partial perspective view of another alternative embodiment of a firearm magazine capacity limiter according to the present invention, showing the muzzle end of a firearm having a tubular magazine, illustrating installation of the magazine capacity limiter directly into the forward end of the tubular magazine of the firearm. 
       
    
    
       [0022]    Similar reference characters denote corresponding features consistently throughout the attached drawings. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0023]    The firearm magazine capacity limiter includes several embodiments, each comprising a rigid rod that is inserted into the magazine and extends through the internal volume of the magazine to limit the travel of the follower within the magazine. The limited travel of the follower, in turn, limits the number of cartridges or rounds of ammunition that may be placed in the magazine. 
         [0024]      FIG. 1  of the drawings provides an exploded perspective view of a first embodiment of a firearm magazine capacity limiter  10 , shown with one side of the magazine  50  removed in order to show the internal structure.  FIG. 2  illustrates the same embodiment of the capacity limiter  10  completely installed in the magazine  50 . The magazine  50  is a detachable box-type magazine having an open cartridge insertion end  52 , an opposite closure plate  54 , the magazine  50  defining an internal ammunition capacity volume  56  between the ends of the magazine  50 . A follower  58  slides within the internal volume  56 . A compression spring  60  captured between the closure plate  54  and the follower  58  urges the follower  58  toward the cartridge insertion end  52  of the magazine  50 , but may be compressed toward the closure plate  54  as cartridges are inserted through the open cartridge insertion end  52 . 
         [0025]    In the embodiment of  FIGS. 1 and 2 , the closure plate  54  includes a thickened or projecting boss  62  having an internally threaded capacity limiter passage  64  that extends through the closure plate  54 . The magazine capacity limiter  10  comprises the boss  62  in combination with a rigid, elongate magazine insert rod  12  having a follower contact end  14  and an opposite closure plate attachment end  16 . The two ends  14  and  16  define a length  18  therebetween. A closure plate attachment fitting  20  is installed upon the closure plate attachment end  16  of the rod  12 . The fitting  20  has an externally threaded portion  22  that threads into the capacity limiter passage  64  (threaded bore) defined by the boss  62 . A knob or handle  24  is preferably provided adjacent to the threaded portion  22  to facilitate installation and removal of the limiter rod  12  in the magazine  50 . The knob  24  may be formed integrally with the threaded portion  22 , or may be formed as a separate component and attached to the closure plate attachment end  16  of the capacity limiter  10  by any suitable means, e.g., a setscrew  26 , etc. The knob  24  may be knurled to facilitate grasping and twisting the rod  12 . 
         [0026]      FIG. 2  illustrates the installation of the magazine capacity limiter rod  12  into the magazine  50  by threading the fitting portion  22  into the mating passage  64  of the boss  62 . It will be seen in  FIG. 2  that the installation of the magazine capacity limiter  10  into the magazine  50  results in the shaft of the elongate magazine insert rod  12  extending partially through the internal ammunition capacity volume  56  of the magazine  50  toward the cartridge insertion end  52  thereof. As more rounds or cartridges are inserted into the magazine  50 , the follower  58  is pushed toward the closure plate  54 . However, well before reaching the closure plate  54 , the follower  58  is stopped by contact with and bearing against the follower contact end  14  of the capacity limiter rod  12 , thus limiting the number of rounds or cartridges that may be inserted into the magazine  50 . 
         [0027]      FIGS. 3A through 3C  provide side elevation views of similar firearm magazine capacity limiters  100   a,    100   b,  and  100   c,  respectively, and a corresponding magazine  150 . The magazine  150  is the same in each of  FIGS. 3A through 3C . The various magazine capacity limiters  100   a  through  100   c  are configured much like the capacity limiter  10  of  FIGS. 1 and 2 , including magazine insert rods  102   a  through  102   c  having follower contact ends  104   a  through  104   c  and opposite closure plate attachment ends  106   a  through  106   c  defining rod lengths  108   a  through  108   c,  closure plate attachment fittings  110   a  through  110   c  having externally threaded portions  112   a  through  112   c  extending from the respective attachment ends  106   a  through  106   c  of the rods, and knobs  114   a  through  114   c  extending beyond the threaded portions. 
         [0028]    The primary difference between the three magazine capacity limiters  100   a  through  100   c  of  FIGS. 3A through 3C  is in the lengths of their respective insert rods  102   a  through  102   c,  both their absolute lengths and their lengths relative to the height or depth of the magazine  150 . The insert rod  102   a  of  FIG. 3A  is longer than rods  102   b  and  102   c  of  FIGS. 3B and 3C  in order to limit the internal ammunition capacity of the magazine  150  to a greater extent than the other capacity limiters  100   b  and  100   c.  The insert rod  102   b  of  FIG. 3B  has an intermediate length  108   b,  while the insert rod  102   c  of  FIG. 3C  has the shortest length  108   c  in order to provide a greater internal ammunition volume for the magazine  150 , while still limiting the capacity to less than its unrestricted volume. The various magazine capacity limiters  100   a  through  100   c  may be provided individually, or as a kit containing two or more capacity limiters, enabling the shooter to use the appropriate magazine capacity limiter  100   a ,  100   b,  or  100   c  according to the laws or regulations in effect at the time and place. 
         [0029]    The magazine  150  of  FIGS. 3A through 3C  is similar to the magazine  50  of  FIGS. 1A and 1B , except for the capacity limiter installation passage. In the magazine  150  of  FIGS. 3A through 3C , the thickened boss has been eliminated and the threaded passage  164  has been formed directly through the closure plate  154 . As the closure plate of a detachable box-type magazine is generally relatively thin, it is preferred that some additional thickness be provided for structural strength for the threaded passage. However, in certain circumstances it may be acceptable to eliminate the boss and provide only a threaded aperture through the thickness of the closure plate  154 , as shown in  FIGS. 3A through 3C . 
         [0030]      FIGS. 4A and 4B  illustrate alternative attachment mechanisms for installing the magazine capacity limiter in the magazine. The magazines  250  are identical to one another and only partially shown in each of the drawings.  FIG. 4A  illustrates a firearm magazine capacity limiter  200  including a magazine insert rod  212  having a follower contact end  214 , an opposite closure plate attachment end  216 , and a length  218  defined between the ends  214 ,  216 . The capacity limiter  200  differs from other embodiments in that the closure plate attachment fitting  220  comprises an unthreaded bushing  222   a  having a tab  222   b  extending radially therefrom, the tab  222   b  being spaced apart from the knob  224  to define a slot having a height slightly greater than the thickness of the plate  254 . The bushing  222   a  is fixed to the rod  212  by friction or pressure fit or otherwise so that the tab  22   b  rotates with the rod  212 . 
         [0031]    The closure plate  254  of the magazine  250  has an unthreaded passage  264   a  formed therein having a slot  264   b  extending radially therefrom. The passage  264   a  and its slot  264   b  are substantially congruent to the bushing  222   a  and tab  222   b  of the magazine capacity limiter  200 . The magazine capacity limiter  200  is secured in the magazine  250  by inserting the bushing  222   a  through the passage  264   a  of the magazine  250  with the tab  222   b  aligned with the slot  264   b  of the magazine  200  and above the closure plate  254 . The capacity limiter  200  is then rotated through a partial revolution to position the tab  222   b  beyond the edge of the closure plate passage  264   a  and out of alignment with the slot  264   b,  thereby locking the magazine capacity limiter  200  in place in the magazine  250 . 
         [0032]      FIG. 4B  illustrates an embodiment similar to that of  FIG. 4A . The firearm magazine capacity limiter  300  of  FIG. 4B  is installed in the same magazine configuration  250  as that of  FIG. 4A . The capacity limiter  300  has a magazine insert rod  312  having a follower contact end  314 , an opposite closure plate attachment end  316 , and a length  318  defined between the ends  314 ,  316 . The rod  312  differs from other embodiments in that the closure plate attachment fitting  320  comprises an annular flange  322   b  defining a slot  322   a  between the flange  322   b  and the knob  324 , the rod  312  having a diameter slightly smaller than the width of the slot or passage extension  264   b  and the slot  322   a  having a height slightly greater than the thickness of the plate  254 . The passage of the magazine closure plate  254  comprises an insertion portion  264   a  having a diameter substantially equal to, or very slightly larger than, the flange  322   b  of the rod  312 . The insertion portion  264   a  and its extension  264   b  are the same as the unthreaded passage  264   a  and slot  264   b  described further above in the discussion of the magazine capacity limiter  200  of  FIG. 4A . The capacity limiter  300  is secured in the magazine  250  by inserting the flange  322   b  through the passage  264   a  of the magazine  250  until the slot  322   a  is coplanar with the closure plate  254 . The rod  312  is then slid laterally to position the shaft of the rod  312  in the slot or extension  264   b,  the closure plate  254  being captured in the slot  322   a  between the flange  322   b  and the knob  324 , thereby locking the rod  312  in place in the magazine  250 . 
         [0033]      FIGS. 5A and 5B  illustrate further embodiments of the firearm magazine capacity limiter, wherein the limiter is adapted for use with firearms having tubular magazines, such as shotguns.  FIG. 5A  illustrates the muzzle end of a firearm having a tubular magazine  450  installed beneath the barrel. The magazine  450  has a hollow tubular interior  452  and an internally threaded end  454   a  and an external rim  454   b  that is normally closed by a cap threaded therein. The cap provides a closure plate for the tubular magazine. The magazine capacity limiter  400  is similar to other embodiments, including a magazine insert rod  412  having a follower contact end  414 , an opposite closure plate attachment end  416 , and a length  418  defined between the ends  414 ,  416 . A threaded closure plate attachment fitting  420  extends from the closure plate attachment end  416 , and a knob  424  extends from the attachment fitting  420 . 
         [0034]    The closure plate  456  of the tubular magazine  450  comprises a cap having an externally threaded portion  458  adapted to thread into the internally threaded end  454  of the tubular magazine  450 , and a larger diameter knob portion  460  extending concentrically therefrom. An internally threaded boss  462  extends concentrically from the knob  460 , i.e., the knob  460  is located between the externally threaded portion  458  and the internally threaded boss  462 . 
         [0035]    The rod  412  is installed in the tubular magazine  450  by first threading the externally threaded portion  458  of the closure plate or cap  456  into the threaded end  454  of the magazine  450 , and then threading the closure plate attachment fitting  420  into the internally threaded boss  462  of the closure plate or cap  456 . The magazine insert rod  412  extends substantially concentrically down the tubular magazine  450  to limit the travel of a follower or shells placed in the magazine from its opposite end, as such magazines are conventionally loaded. 
         [0036]      FIG. 5B  illustrates another embodiment of the firearm magazine capacity limiter, designated as capacity limiter  500 . The tubular firearm magazine  450  and its internally threaded forward end  454   a  and its external rim or lip  454   b  are the same as the magazine and internally threaded end thereof shown in  FIG. 5A . However, it will be seen in  FIG. 5B  that the magazine  450  does not have a closure plate in this embodiment. The magazine capacity limiter  500  includes a magazine insert rod  512  having a follower contact end  514 , an opposite closure plate attachment end  516 , and a length  518  defined between the ends  514 ,  516 . An externally threaded bushing  520  is mounted on the closure plate attachment end  516  by pressure or friction fit, and a manipulation knob  524  extends from the attachment bushing  520 . 
         [0037]    The closure plate attachment bushing  520  threads directly into the internally threaded end  454   a  of the tubular magazine  450 . The rod  512  is installed in the tubular magazine  450  by threading the closure plate attachment bushing  520  into the internally threaded end  454   a  of the magazine  450 . The external rim  454   b  of the magazine  450  serves as a limiting stop for the rod  512  in the magazine  450 . The magazine insert rod  512  extends substantially concentrically down the tubular magazine  450  to limit the travel of a follower or shells placed in the magazine from its opposite end, as such magazines are conventionally loaded. 
         [0038]    It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.