Abstract:
A firearm and a jig for modifying or constructing a firearm with a locking magazine release button is provided. The firearm has a lower receiver including a magazine locking pin aperture disposed in an upper surface thereof where the magazine locking aperture intersects with a magazine release button aperture in a side surface of the lower receiver. The firearm also has an upper receiver attached to the lower receiver via a pivot pin, a magazine attachable to the lower receiver, a magazine locking pin inserted into the magazine locking pin aperture, and a magazine release button comprising a recessed locking catch. The magazine release button releases the magazine when the upper receiver is away from the lower and the pin is not in the magazine locking aperture. The button is inoperable when the upper receiver is next to the lower receiver and the pin engages the locking catch.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to U.S. Provisional Application No. 62/363,787 which was filed on Jul. 18, 2016, the contents of which are hereby incorporated by reference. 
     
    
     BACKGROUND 
     1. Field 
       [0002]    The disclosed embodiments relate to firearms. More specifically the disclosed embodiments relate to methods and systems for modifying a magazine locking mechanism of a firearm, and a firearm with a locking magazine release. 
       2. Related Art 
       [0003]    Laws and policy controlling the sale and transfer of firearms continue to evolve. Some jurisdictions have considered or have passed various regulations attempting to prevent firearms from being sold that would enable a criminal or terrorist to shoot multiple rounds of ammunition in a short period of time. Such laws are often politically controversial. However, the result is a demand to develop new firearms that comply with such regulations or to develop methods and systems to modify existing firearms so that such firearms are compliant with the regulations. 
         [0004]    An example of such a regulation passed in California classifies weapons with magazine release button that allow for the quick removal and reinstallation of magazines as assault rifles. This includes magazine release buttons that require tools to operate. The regulation requires current owners of such weapons to register the firearm as a registered assault weapon (RAW). Transfer of a RAW under the regulations is prohibited, event in the event of death. 
         [0005]    For a firearm to not be considered an assault rifle, the firearm&#39;s action must be open for the magazine to be released. One way this is done is for the firearm to be at least partially disassembled to remove the magazine. 
         [0006]    Examples of firearms that have a magazine release button to remove a magazine include the popular AR-15 rifle, including the many variations on the AR-15 platform, and the AR-308. An example of an AR-15 rifle  100  is shown in  FIGS. 1A and 1B . The rifle  100  has a magazine release button  102  that releases a magazine  104  for quick removal of the magazine  104  to quickly reinstall a new magazine  104 . Thus, the typical AR-15 rifle would likely be considered an assault rifle under the California regulation. 
         [0007]    Given the popularity of the AR-15, there are proposed methods of modifying the rifle to comply with the regulation. In these proposals, the rifle  100  is modified so that the magazine release button  102  is rendered inoperable until after the rifle  100  is disassembled such that the rifle cannot be fired. For example, the rifle is modified so that a magazine release button  102  will not work until a rear take down pin  108  is removed and the upper receiver  110  is pivoted away from the lower receiver  112  via the pivot pin  106 . 
         [0008]    In these previously proposed methods, the modifications to the gun may be considered unsightly. For example, the previous proposed modifications require a large, thick lever arm between the upper receiver and the magazine release button. Further, the required pivoting of the upper receiver with respect to the lower receiver for the magazine release button to enable is large, making the process awkward. Many of the proposed modifications also require epoxy to make the modified parts unremovable from the outside. 
         [0009]    In some cases, the rifle will double feed. In this case, the bolt carrier group is partially locked back and one round is partially in the chamber, the second is either ½ in the mag and into the barrel area or inside of the gun. The safe way to clear this is to remove the magazine and drop out the extra rounds and to pull back the charging handle. Since the bolt is partially retracted, a user can&#39;t rotate the upper out of the way to clear the magazine release so a user has to clear this with the magazine in the firearm making it dangerous. In the other designs, the retracted or partially retracted bolt carrier group prevents the action from opening and releasing the magazine. 
         [0010]    Accordingly, more convenient, safe, and attractive modifications are necessary to modify a rifle so that it can be compliant with such regulations. 
       SUMMARY 
       [0011]    Accordingly, systems and methods for modifying a firearm, and a firearm design have been developed that safely and conveniently allow for disassembly of a firearm to disengage the action to allow a magazine to be release. In one embodiment, a jig for modifying a magazine release mechanism is provided. The jig includes mounting blocks that are releasably attached to a take-down pin and a pivot pin of a lower receiver of a firearm, and a base plate attached to the mounting blocks. The base plate includes a plurality of drill gauges, at least one drill guide aperture, a magazine release button recess that removably attaches to a magazine release button; and at least one drill guide that is removably inserted into the at least one drill guide aperture. 
         [0012]    In some embodiments, the base plate also includes at least one locating feature to position the jig on the lower receiver of the firearm. The at least one locating feature may include a lip protruding from a bottom surface and/or a vertical extension projecting from the bottom surface. The vertical extension may be aligned with the at least one drill guide aperture and may include a set screw drill hole aperture that extends through the vertical extension parallel to the bottom surface. 
         [0013]    In one embodiment, the magazine release button recess is formed on a bottom surface of the base plate and overlaps the at least one drill guide aperture. The magazine release button recess may have an oval shape. 
         [0014]    In another embodiment, a speed cam is provided that is configured to replace a take-down pin of a firearm having a lower and an upper receiver. The speed cam includes a head disposed at a first end that has a projection that interfaces with a lever arm, an annular groove disposed adjacent to the head that has at least one detent, an intermediate cylindrical surface disposed adjacent to the annular groove, a terminal cylindrical surface disposed at a second end, and cam surfaces disposed between the intermediate cylindrical surface and the terminal cylindrical surface. The cam surfaces interface with the upper receiver to define an open position between the upper receiver and the lower receiver, a locked position between the upper receiver and the lower receiver, and a removable position between the upper receiver and the lower receiver. 
         [0015]    In one embodiment, the cam surfaces include a locking cam surface having a radius similar to the intermediate cylindrical surface and the terminal cylindrical surface. The locking cam surfaces hold the upper receiver next to the lower receiver in a locked position. The cam surfaces may also comprise an open cam surface having a radius less than the intermediate cylindrical surface and the terminal cylindrical surface. This smaller radius allows the upper receiver to pivot away from the lower receiver. In this position, the action is disengaged and the magazine may be released from the firearm. 
         [0016]    The speed cam may further include an axial groove extending through the intermediate cylindrical surface and into the terminal cylindrical surface. The axial groove comprises a stop detent disposed toward the second end. The axial groove allows the speed cam to be pulled out to clear the upper receiver, allowing the upper receiver to be fully disassembled from the lower receiver. 
         [0017]    In yet another embodiment, a firearm with a locking magazine release button is provided. The firearm includes a lower receiver having a magazine locking pin aperture on a top surface that extends to intersect with a magazine release button aperture in a side surface. An upper receiver is attached to the lower receiver via a pivot pin where the upper receiver may pivot relative to the lower receiver via the pivot pin. 
         [0018]    A magazine is provided that releasably attaches to the lower receiver, and a magazine locking pin is included that is inserted into the magazine locking pin aperture. A magazine release button is disposed in the magazine release button aperture and includes a recessed locking catch. The magazine release button releases the magazine when the upper receiver is pivoted away from the lower receiver and the magazine locking pin does not extend into the magazine locking aperture. The magazine release button is inoperable to release the magazine when the upper receiver is next to the lower receiver and the magazine locking pin extends into the magazine locking aperture and engages the recessed locking catch. 
         [0019]    In some embodiments, the firearm further comprises a take-down pin connecting the upper receiver and the lower receiver. The take-down pin locks the upper receiver to the lower receiver and prevents the upper receiving from pivoting away from the lower receiver. The magazine locking pin includes a large diameter portion and a small diameter portion, and a spring disposed within the magazine locking pin aperture biases the magazine locking pin out of the magazine locking pin aperture. 
         [0020]    The magazine locking pin aperture may include a threaded hole in a sidewall thereof. The magazine locking pin may include a u-shaped recess defining a locking seat. A set screw disposed in the threaded hole engages the locking seat to lock the magazine locking pin within the magazine locking pin aperture. The firearm may include a speed cam as described above. 
         [0021]    The firearm results in a locking and unlocking magazine release button that can release the magazine when the action is open a small amount where the bolt carrier group is partially or fully retracted. Legal magazine changes are facilitated when the bolt carrier group is fully retracted and held in place by the bolt catch. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]      FIG. 1A  and  FIG. 1B  show an exemplary rifle. 
           [0023]      FIG. 2A  shows an unassembled view of a jig for modifying a magazine locking mechanism, and  FIG. 2B  shows an assembled view of the jig in  FIG. 2A . 
           [0024]      FIG. 3A ,  FIG. 3B ,  FIG. 3D ,  FIG. 3D , and  FIG. 3E  show steps of using a jig for modifying magazine locking mechanism, according to an exemplary embodiment. 
           [0025]      FIG. 4A ,  FIG. 4B ,  FIG. 4C ,  FIG. 4D ,  FIG. 4E , and  FIG. 4F  show steps of using a jig for modifying a magazine release button, according to an exemplary embodiment. 
           [0026]      FIG. 5  shows a magazine locking pin, according to one exemplary embodiment. 
           [0027]      FIG. 6A ,  FIG. 6B ,  FIG. 6C , and  FIG. 6D  show assembly steps of adding a magazine locking pin to a firearm, according to an exemplary embodiment. 
           [0028]      FIG. 7A  and  FIG. 7B  show installation of a modified magazine locking button, according to one exemplary embodiment. 
           [0029]      FIGS. 8A and 8B  show operation of a firearm with a modified magazine lock, according to an exemplary embodiment. 
           [0030]      FIG. 9A ,  FIG. 9B , and  FIG. 9C  show a speed cam assembly, according to an exemplary embodiment. 
           [0031]      FIG. 10A ,  FIG. 10B , and  FIG. 10C  show operation of a speed cam assembly, according to an exemplary embodiment. 
       
    
    
       [0032]    The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the figures, like reference numerals designate corresponding parts throughout the different views. 
       DETAILED DESCRIPTION OF EMBODIMENTS 
       [0033]    Described below are jigs, methods, and systems for modifying a firearm to have a locked magazine until an action of the firearm is disengaged. Reference is made throughout the specification and figures to an AR-15 rifle to facilitate explanation. However, the jigs, methods, and systems may be applied to several other weapons systems and are not limited to the AR-15. 
         [0034]      FIG. 2A  shows an unassembled view of a jig for modifying a magazine locking mechanism, and  FIG. 2B  shows an assembled view of the jig in  FIG. 2A . A magazine locking assembly modification jig  200  is comprised of a baseplate  210  having a top side  202 , a bottom side  204 , a first end  206 , and a second end  208 . The base plate  210  comprises several features to enable modification of a firearm, such as an AR-15 rifle. 
         [0035]    The base plate  210  comprises drill guide holes that provide templates for modifying parts of the rifle. A magazine lock pin guide hole  212  is disposed on a center portion of the base plate  210  and extends through from the top side  202  to the bottom side  204 . A magazine lock catch guide hole  214  is also provided extending from the top side  202  to the bottom side  204 . 
         [0036]    On the top side  202  of the base plate  210 , a first depth gauge  216 , a second depth gauge  218 , and a third depth gauge  220  are provided. These depth gauges  216 ,  218 ,  220  accurately set drill depths for modified features of the rifle as will be discussed in more detail below. The depth gauges  216 ,  218 ,  220  extend from a lateral edge of the base plate  210  and are disposed towards the second end  208 . 
         [0037]    Additional depth gauges  226 ,  227  extend on the top side  202  of the base plate  210  from the first end. These depth gauges  226 ,  227  accurately set drill depths for other modified features of the rifle as discussed below. Apertures  222 ,  224  are provided to attach mounting blocks  230 , as shown in  FIG. 2B . The apertures  222 ,  224  are formed in an oval shape to accommodate a universal fit to several gun types. The mounting blocks  230  are configured to reference the jig  200  to a lower receiver of a rifle. Here, the mounting blocks  230  mount to the pivot pin and take down pin of an AR-15 rifle (see pivot pin  106  and takedown pin  108  in  FIG. 1B ). A width of the jig  200  is formed to be wider than the lower receiver so that the jig can be held in in a clamping device, such as a vise, to facilitate work on the lower receiver. 
         [0038]    The base plate  210  further comprises a vertical extension  228  that projects downward from the bottom side  204 . This feature further helps to orient the base plate  210  relative to the lower receiver of the rifle. Aperture  229  may be threaded and provides access to the magazine lock pin guide hole  212  to lock drill guides  232 ,  234  within the hole  212 . Fasteners  236  are provided to attach the mounting blocks  230  and fix the drill guides  232 ,  234 . The base plate also has a lip  240  projecting slightly from the bottom side  204  to reference the jig  200  to the lower receiver to provide the correct spacing between the lower receiver and the jig  200 . The combination of the mounting blocks  230 , the vertical extension  228  and lip  240  ensures the correct positioning of the jig  200  in each of the x-, y-, and z-directions (the x-direction referring to the direction from the first end  206  to the second end  208 , the y-direction referring to a direction perpendicular to the x-direction and parallel with the top side  202  and bottom side  204  of the base plate  210 , and the z-direction referring to a direction perpendicular to a plane defined by the top side  202  and the bottom side  204  of the base plate  210 ) as well as at the correct rotation position. 
         [0039]      FIG. 3A ,  FIG. 3B ,  FIG. 3D ,  FIG. 3D , and  FIG. 3E  show steps of using a jig for modifying a lower receiver to accommodate a magazine locking mechanism, according to an exemplary embodiment. After the jig  200  is attached to the lower receiver of the rifle, a hole to facilitate a magazine locking pin may be drilled. As shown in  FIG. 3A , a drill bit  310  is placed in the drill bit depth gauge  227  to set a drill stop  312  to control a drill depth for the drill bit  310 . In  FIG. 3B , the drill bit  310  is inserted into the first drill guide  232  to drill a hole with a first width in the lower receiver to accommodate the magazine locking pin. The first drill guide  232  is then replaced with the second drill guide  234  (see  FIG. 3C ), and a hole for the magazine locking pin is extended with a second width that is narrower than the first width. The depth of the extended part of the hole is set by the third depth gauge  220 . This forms a spring seat within the magazine locking pin hole, as will be explained in more detail below. 
         [0040]    A retaining screw hole is formed on a side of the magazine locking pin hole by setting a drill depth of a drill bit  314  using the second drill gauge  218  as shown in  FIG. 3C . The vertical extension  228  of the base plate  210  further comprises a transverse hole  242  through which the drill bit  314  is inserted as shown in  FIG. 3D  to drill the retaining screw hole. After the retaining screw hole is formed, it is tapped with female threads.  FIG. 3E  shows a resulting magazine locking pin hole  350  with the retaining screw hole  352 . As mentioned above, the pin hole  350  has a larger upper diameter and a smaller lower diameter that form a spring seat. 
         [0041]      FIG. 4A ,  FIG. 4B ,  FIG. 4C ,  FIG. 4D ,  FIG. 4E , and  FIG. 4F  show steps of using a jig for modifying a magazine release button, according to an exemplary embodiment. As shown in  FIG. 4A , the base plate  210  comprises a recessed oval  244  in the bottom surface  204 . The recessed oval  244  is located to at least partially overlap with the magazine lock catch guide hole  214 . A threaded screw hole  246  is disposed in the base plate  210  within the recessed oval  244 . 
         [0042]    In  FIG. 4B , a magazine release button  410  fits within the recessed oval  244  and is fastened to the base plate  210  via a fastener  326 . Drill bit  310  is set to a drill depth via the drill gauge  226  with the drill stop  312  as shown in  FIG. 4C . In  FIG. 4D , the drill guide  232  is placed in the magazine lock catch guide hole  214 . The drill bit  310  at the set drill depth machines out a locking catch  412  in the release button  410  ( FIG. 4F ). A drill depth for a second drill bit is set via the first drill gauge  216  as shown in  FIG. 4E . Using hole  248  as a guide, a set screw hole  414  is formed in the magazine release button  410  ( FIG. 4F ). This hole is tapped with female threads to receive a set screw. 
         [0043]      FIG. 5  shows a magazine locking pin, according to one exemplary embodiment. A magazine locking pin  500  comprises a large diameter portion  510  and a small diameter portion  520 . A spring  530  is disposed over the small diameter portion  520  and abuts against the large diameter portion  510 . In use, the spring is placed into the pin hole  350  and is seated on the spring seat to bias the large diameter portion  510  away from the spring seat. The large diameter portion  510  has a u-shaped recess  512  formed therein forming two extensions  514  and a locking seat  516  at the bottom of the u-shaped recess  512 . 
         [0044]      FIG. 6A ,  FIG. 6B ,  FIG. 6C , and  FIG. 6D  show assembly steps of adding a magazine locking pin to a firearm, according to an exemplary embodiment. In  FIG. 6A , the magazine locking pin  500  is inserted into the magazine locking pin hole  350 . The spring  530  biases the pin  500  out of the hole as explained above.  FIG. 6B  shows an upper receiver  110  and a lower receiver  112  in an assembled position where the upper receiver  110  is directly adjacent to the lower receiver  112 . The lower receiver comprises a magazine release button aperture  114 . In this position, the upper receiver  110  forces the pin  500  down so that the extensions  514  are flush with the top of the lower receiver  112 . The small diameter portion  510  of the pin  500  extends into the magazine release button aperture  114  via the small diameter portion of the pin hole  350 . 
         [0045]    When the upper receiver  110  is pivoted away from the lower receiver  112 , the spring biases the pin  500  upwards so that the small diameter portion  510  no longer protrudes into the magazine release button aperture  114 . As shown in  FIG. 6D , a set screw  602  within the hole  352  of the magazine locking pin hole  350  engages the locking seat  516  to lock the pin  500  within the hole  350  preventing the pin  500  from falling out when upper receiver  110  is pivoted away from the lower receiver  112 . For example, when the pin  500  is biased out of the hole  350  by the spring  530 , the set screw  602  comes into contact with the locking seat  516  to prevent further movement of the pin  500  out of the hole  350 . This screw  602  also prevents the rotation of the pin  500  within the hole  350 . 
         [0046]      FIG. 7A  and  FIG. 7B  show installation of a modified magazine locking button, according to one exemplary embodiment. The magazine release button  410  is inserted and secured into the magazine release button aperture  114 . The magazine release button  410  may be biased towards the outside of the lower receiver  112  via a spring  702 . The locking catch  412  is positioned on the upward side of the magazine release button aperture  114  to interface with the pin  500 . To ensure a good fit and interaction between the locking catch  412  and the pin  500 , a set screw  704  may be used as shown in  FIG. 7B . The adjustment of the set screw as shown in  FIG. 7B  ensures that the locking catch  412  is correctly positioned at the top side of the magazine release button aperture  114  and eliminates excessive play between the magazine release button and the magazine release button aperture  114 . 
         [0047]      FIGS. 8A and 8B  show operation of a firearm with a modified magazine lock, according to an exemplary embodiment. In  FIG. 8A , the upper receiver  112  is locked next to the lower receiver  110  by the take down pin  108 . In this position, the pin  500  interacts with the locking catch  412 , preventing the magazine  104  from releasing from the lower receiver  112 . When the take-down pin  108  is removed as shown in  FIG. 8B , the upper receiver  110  may rotate about the pivot pin  106 . The pin  500  moves upward and the magazine release button  410  may be actuated to release the magazine  104 . 
         [0048]      FIG. 9A ,  FIG. 9B , and  FIG. 9C  show a speed cam assembly, according to an exemplary embodiment. In  FIG. 9A , a speed cam assembly  900  includes a speed cam  902 , a lever arm  990 , and fastener  998 . The speed cam  902  has a first end  904  and a second end  906 . At a first end  904  of the speed cam, a speed cam head  908  is provided with a projection  910  for applying a torque to the speed cam  902 . The projection  910  comprises a threaded aperture  912  by which the fastener  998  secures the lever arm  990  to the speed cam  900 . 
         [0049]    The lever arm  990  comprises an arm portion  992  and an aperture  994  through which the fastener  998  may pass. The lever arm  900  further comprises a slot  996  on a rear side that engages the projection  910  so that a force applied on the arm portion  992  is transferred to the projection  910  to rotate the speed cam  902 . 
         [0050]    The first end  904  of the speed cam  902  further comprises an annular groove  916  between an intermediate cylindrical surface  914  and the head  908 . The annular groove  916  comprises three detents  918 . The annular groove  916  and detents  918  engage a projection or pin found in the upper receiver  112  of a firearm that typically engages with a conventional take down pin  108 . The three detents  918  define three annular positions of the speed cam: a locked position, an open position, and removable position. The detents  918  provide tactile feedback to a user so that the user can feel when the speed cam assembly  900  is in one of the locked, open, and removable positions. The annular groove  916  allows the speed cam  902  to rotate with the pin of the upper receiver being held within the annular groove  915  by the head  908  and the intermediate cylindrical surface  914 . This allows rotation of the speed cam  902  but prevents the removal of the speed cam  902 . 
         [0051]    On the second end  906  of the speed cam  902 , a terminal cylindrical surface  920  is provided. The intermediate cylindrical surface  914  and terminal cylindrical surface  920  allow the speed cam to rotate within standard apertures of an upper and lower receiver  110 ,  112  that receive the take down pin  108 . 
         [0052]    In  FIG. 9B , locking cam surfaces  922  are provided that have a radius similar to the terminal cylindrical surface  920 . The locking cam surfaces  922  interact with the upper receiver  110  to secure the upper receiver when the speed cam is rotated to the locked and closed position. When the speed cam  902  is rotated to the removable position, the projection of the upper receiver  110  aligns with the detent  918  adjacent to a groove  924 . The groove allows the speed cam  902  to be removed like a conventional take-down pin  108 . An additional detent  926  is provided at the end of the groove  924  on the second end  906  of the speed cam  902 . This gives tactile feedback to the user that the speed cam  902  has cleared the upper receiver  110  for disassembly. 
         [0053]      FIG. 9C  shows open cam surfaces  928 . The open cam surface  928  have a radius less than the radius of the intermediate cylindrical surface  914  and the terminal cylindrical surface  920 . The smaller radius allows the upper receiver  110  to pivot away from the lower receiver  112  when the speed cam is rotated to the open position. 
         [0054]      FIG. 10A ,  FIG. 10B , and  FIG. 10C  show operation of a speed cam assembly, according to an exemplary embodiment. In  FIG. 10A , the speed cam assembly  900  is rotated to the open position. In this position, the speed cam  902  allows the upper receiver  110  to rotate slightly away from the lower receiver  112 . This allows the pin  500  to raise so that the magazine release button  410  may operate to release the magazine  104 . Though the rotation shown is slight, it is sufficient for the action of the firearm to be disengaged and for the pin  500  to no longer interface with the locking catch  412  of the release button. 
         [0055]    In  FIG. 10B , the speed cam assembly  900  is rotated to the locked position. In this position, the upper receiver  110  is held firmly against the lower receiver  112 . In  FIG. 10C , the speed cam assembly  900  is rotated to the removable position and is pulled out to clear the upper receiver  112  allowing the upper receiver  112  to be completely disassembled from the lower receiver  110 . Thus, a user can conveniently operate the firearm. 
         [0056]    While various embodiments of the invention have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible that are within the scope of this invention. In addition, the various features, elements, and embodiments described herein may be claimed or combined in any combination or arrangement.