Patent Publication Number: US-9885531-B2

Title: Semi-automatic firearm rapid-fire accessory

Description:
BACKGROUND 
     Various techniques and devices increase the firing rate of a semi-automatic firearm. Bump firing is a technique of firing a semi-automatic firearm using the recoil energy from firing the weapon to rapid-fire faster than what an operator could achieve by repeated finger pulls. 
     Operators may bump fire a semi-automatic firearm without the use of tools, accessories, or alterations to the weapon, but such freehand techniques are difficult to master. To execute a freehand technique, the operator generally holds the semi-automatic firearm away from his or her body in order to allow the weapon to recoil after firing. One freehand technique has the operator hold a trigger hand in a rigid position with a trigger finger just in front of the trigger while placing a forend hand (i.e., the other hand) on a hand guard of the weapon. The hand guard generally covers the barrel of the semi-automatic firearm, which is forward of the trigger. Using the forend hand to push the hand guard forward, while maintaining the trigger hand in the rigid position, the semi-automatic firearm shifts forward relative to the trigger hand This forward movement causes the trigger to engage the trigger finger, which if held firmly in the rigid position will discharge the semi-automatic firearm. Recoil from the discharge of a bullet pushes the semi-automatic firearm rearwards away from the trigger finger, allowing the trigger to re-set. If the operator maintains a forward force on the hand guard while keeping the trigger hand stationary in the rigid position (i.e., pulling the forend hand away from the trigger hand), the operator will be able to once again push the hand guard forward after the recoil energy dissipates, which once again discharges the weapon. By continuously maintaining the forward force on the hand guard with the trigger hand in the rigid position, the weapon will discharge in a rapid-fire succession that is generally faster than what the operator can achieve with repeated finger pulls. Not all operators that attempt this technique are successful or consistently successful. 
     SUMMARY 
     Devices, systems, and methods of various embodiments are disclosed including a rapid-fire accessory for a semi-automatic firearm. The rapid-fire accessory may include a trigger guard mount and a trigger actuator. The trigger guard mount may attach the rapid-fire accessory to the semi-automatic firearm. The trigger guard mount may include a mounting channel for receiving a trigger guard of the semi-automatic firearm. When mounted in the mounting channel, the trigger guard guides a sliding movement of the trigger guard mount forward and rearward relative to the trigger guard. The trigger actuator may engage a trigger of the semi-automatic firearm. The trigger actuator may be fixed relative to the mounting channel and configured to pull the trigger when the trigger guard slides forward in the mounting channel. 
     Various embodiments include a receiving aperture in the mounting channel on a lateral side of the mounting channel for inserting the trigger guard into the mounting channel. A detent may protrude across a portion of the receiving aperture for trapping the trigger guard in the mounting channel. The mounting channel may be formed by an upper wall, a lower wall opposed to the upper wall, and a lateral wall connecting the lower wall and the upper wall. The trigger guard may be in sliding engagement with at least one of the lower wall and the upper wall during the sliding movement. When the trigger guard is mounted in the mounting channel, the upper wall may be disposed between the trigger and the trigger guard. The mounting channel may include a receiving aperture for inserting the trigger guard in the mounting channel. Flexing a portion of the trigger guard mount may increase a width of the receiving aperture for releasing the trigger guard from the mounting channel The trigger actuator may be formed by a wall of a trigger recess in the trigger guard mount. The mounting channel may be formed by a left wall, a right wall opposed to the left wall, and a lower wall connecting the left wall and the right wall. The trigger guard may be in sliding engagement with the lower wall during the sliding movement. The trigger guard may be disposed between the trigger actuator and the lower wall when the trigger guard is mounted in the mounting channel The trigger actuator may be removably secured to at least one of the left wall and the right wall, wherein removal of the trigger actuator releases the trigger guard from the mounting channel The trigger guard may extend across the mounting channel from a left wall to a right wall opposed to the left wall. The trigger actuator may be a removably secured element. The mounting channel may extend between a trigger finger grip and an opposed thumb grip. 
     Various embodiments include a trigger finger grip that may extend from a lateral side of an upper portion of the trigger guard mount. The trigger finger grip may be configured to engage a trigger finger while the trigger actuator is engaged on the trigger. An extension member may extend from a lateral side of the trigger guard mount rearward away from the trigger actuator. A lower finger grip may protrude from a lower portion of the trigger guard mount. The lower finger grip may be configured to engage a finger of an operator while the operator is firing the semi-automatic firearm. A thumb grip may be disposed remote from the trigger guard mount and configured to engage a thumb of an operator while the operator is firing the semi-automatic firearm. A trigger finger grip may be disposed forward of the trigger actuator. The trigger finger grip may be configured to engage a trigger hand finger of an operator while the operator is firing the semi-automatic firearm. A thumb grip may be disposed rearward from the trigger actuator. The thumb grip may be configured to engage an operator&#39;s thumb while a operator is firing the semi-automatic firearm. 
     Various embodiments include a method of mounting a rapid-fire accessory on a trigger guard of a semi-automatic firearm. The method may include mounting a trigger guard mount of the rapid-fire accessory onto the trigger guard. Once mounted on the semi-automatic firearm, the trigger guard may be disposed in a mounting channel of the trigger guard mount. The trigger guard may guide a sliding movement of the trigger guard mount forward and rearward relative to the trigger guard. The rapid-fire accessory may include a trigger actuator for engaging a trigger of the semi-automatic firearm, wherein the trigger actuator is fixed relative to the mounting channel and configured to pull the trigger when the trigger guard slides forward in the mounting channel. 
     Various embodiments include moving a detent protruding across a portion of the receiving aperture from an initial position to enable the trigger guard to be inserted in the mounting channel Returning the detent to the initial position may trap the trigger guard in the mounting channel 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate example embodiments of the invention, and together with the general description given above and the detailed description given below, serve to explain the features of the invention. 
         FIG. 1A  illustrates a right side view of a rapid-fire accessory on a semi-automatic firearm, shown in phantom, in a ready-to-fire configuration in accordance with various embodiments. 
         FIG. 1B  illustrates a right side view of the rapid-fire accessory on the semi-automatic firearm of  FIG. 1A  in a fired configuration in accordance with various embodiments. 
         FIG. 2A  illustrates a right side view of an operator firing a semi-automatic firearm using a rapid-fire accessory in accordance with various embodiments. 
         FIG. 2B  illustrates a close-up view of the semi-automatic firearm of  FIG. 2A  being handled in the ready-to-fire configuration using a rapid-fire accessory in accordance with various embodiments. 
         FIG. 2C  illustrates a close-up view of the semi-automatic firearm of  FIGS. 2A and 2C  being handled in the fired configuration using a rapid-fire accessory in accordance with various embodiments. 
         FIG. 3A  illustrates a rear-right side downward-looking perspective view of a rapid-fire accessory in accordance with various embodiments. 
         FIG. 3B  illustrates a forward-left side downward-looking perspective view of the rapid-fire accessory of  FIG. 3A  in accordance with various embodiments. 
         FIG. 3C  illustrates a rear-right side upward-looking perspective view of the rapid-fire accessory of  FIGS. 3A and 3B  in accordance with various embodiments. 
         FIG. 3D  illustrates a forward-left side upward-looking perspective view of the rapid-fire accessory of  FIGS. 3A-3C  in accordance with various embodiments. 
         FIG. 4A  illustrates a front elevation view of a partially formed rapid-fire accessory, with a portion of a trigger guard in phantom, in accordance with various embodiments. 
         FIG. 4B  illustrates a rear elevation view of the partially formed rapid-fire accessory of  FIG. 4A  in accordance with various embodiments. 
         FIG. 4C  illustrates a top plan view of the partially formed rapid-fire accessory of  FIGS. 4A and 4B  in accordance with various embodiments. 
         FIG. 4D  illustrates a right side partial-section view at  4 D- 4 D in  FIG. 4C  of the partially formed rapid-fire accessory of  FIGS. 4A-4C , with a portion of a trigger and a trigger guard in phantom, in accordance with various embodiments. 
         FIG. 5A  illustrates a rear left-side downward-looking perspective view of a rapid-fire accessory partially mounted on a semi-automatic firearm in accordance with various embodiments. 
         FIG. 5B  illustrates a bottom view of the rapid-fire accessory partially mounted on a semi-automatic firearm of  FIG. 5A  in accordance with various embodiments. 
         FIG. 6A  illustrates a side elevation view of a rapid-fire accessory positioned separate from and below a semi-automatic firearm in accordance with various embodiments. 
         FIG. 6B  illustrates a side elevation view of the rapid-fire accessory and the semi-automatic firearm of  FIG. 6A  attached together with the semi-automatic firearm in a ready-to-fire configuration in accordance with various embodiments. 
         FIG. 6C  illustrates a side elevation view of the rapid-fire accessory and the semi-automatic firearm of  FIG. 6A  attached together with the semi-automatic firearm in a fired configuration in accordance with various embodiments. 
         FIG. 7A  illustrates a rear-right side downward-looking perspective view of the rapid-fire accessory of  FIG. 6A-6C , without a trigger actuator, in accordance with various embodiments. 
         FIG. 7B  illustrates a forward-left side perspective view of the rapid-fire accessory of  FIG. 6A-7A , without a trigger actuator, in accordance with various embodiments. 
         FIG. 7C  illustrates a forward-right side downward-looking perspective view of the rapid-fire accessory of  FIG. 6A-7B , with a trigger actuator installed, in accordance with various embodiments. 
         FIG. 7D  illustrates a rear-left side upward-looking perspective view of the rapid-fire accessory of  FIG. 6A-7C , without a trigger actuator, in accordance with various embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Various embodiments will be described in detail with reference to the accompanying drawings. Wherever possible the same reference numbers will be used throughout the drawings to refer to the same or like parts. References made to particular examples and implementations are for illustrative purposes, and are not intended to limit the scope of the invention or the claims. 
     Various embodiments include a rapid-fire accessory that mounts onto the triggerguard of a semi-automatic firearm. The rapid-fire accessory does not require the removal or replacement of the original, replacement, or aftermarket firearm grip or other components of the firearm. The rapid-fire accessory provides a structural component an operator may hold that facilitates bump firing the semi-automatic firearm. Once mounted on the semi-automatic firearm, the rapid-fire accessory may slide forward and rearward, using a trigger guard of the semi-automatic firearm as a guiding surface. The rapid-fire accessory also includes finger grips for comfortably and securely holding both the rapid-fire accessory as well as the semi-automatic firearm to assist an operator in bump firing the firearm rapidly utilizing the recoil energy of the firearm. 
     The term “semi-automatic firearm” as used herein refers generally to a portable gun that is configured to self-load by performing all the steps necessary to prepare the weapon to discharge again after firing. A semi-automatic firearm comprises a barreled weapon that launches a series of bullets driven by the action of an explosive force such as gunpowder. A semi-automatic firearm may include any one or all of rifles, shotguns, carbines, and even long-barrel handguns that include a hand guard on the barrel and are suitable for bump firing. Semi-automatic firearms include a receiver into which a cartridge is loaded that holds each bullet until it is fired. In addition, semi-automatic firearms include a barrel, extending from the receiver, and a trigger assembly for firing the weapon. The barrel and/or the receiver may be mounted in or integrally formed into a stock made of wood, plastic, metal, composite, or any combination thereof Semi-automatic firearms generally include various grip surfaces such as the hand guard on the barrel, a butt stock to place against an operator&#39;s shoulder, and/or an intermediate grip surface. 
     The term “trigger” as used herein refers generally to a lever or button mechanism that actuates the firing sequence of a semi-automatic firearm. A trigger may directly or indirectly cause the release of powerful energy (i.e., an explosion) that propels a bullet from the weapon. Triggers are generally configured to be actuated by an index finger, which may also be referred to as the trigger finger, although other fingers may be used. The term “trigger guard” as used herein refers to a structural element that is part of the semi-automatic firearm, such as an original, replacement, or aftermarket part thereof. The trigger guard blocks direct engagement of the trigger from at least below the semi-automatic firearm, which generally requires an operator to approach the trigger with a trigger finger from one of the lateral sides. 
     The term “operator” as used herein refers generally to a person who uses and controls the semi-automatic firearms. An operator generally uses two hands to bump fire a semi-automatic firearm. One hand, used to hold part of the semi-automatic firearm near the trigger, is referred to herein as the “trigger hand ” Generally, an index finger is used as a trigger finger, however any finger on the trigger hand used to pull the trigger may be referred to as the “trigger finger.” Other fingers on the trigger hand not typically used to pull the trigger may be referred to individually as trigger-hand fingers, such as the trigger-hand thumb or the trigger-hand middle finger. The other hand (i.e., the non-trigger hand), may be used to hold a forend of the semi-automatic firearm by way of the hand guard, and is referred to herein as the “forend hand ” 
     In various embodiments, the rapid-fire accessory is illustrated and described with an asymmetric design suitable for a right-handed or left-handed operator. It should be understood that various embodiments may be modified to invert the structures when forming a rapid-fire accessory to accommodate a left-handed operator. In this way, the left side becomes the right side and vise-versa. 
       FIGS. 1A-1B  illustrate a rapid-fire accessory  100  in accordance with various embodiments. In  FIGS. 1A-1B , a semi-automatic firearm  5  and parts thereof (illustrated in phantom lines with gray fill) are shown in ready-to-fire and fired configurations, respectively, with the rapid-fire accessory  100  mounted thereon. In the orientations illustrated in  FIGS. 1A-1B , the semi-automatic firearm  5  is aiming to the right, which is referred to herein as a “forward” direction, which is opposed to a “rearward” direction aiming to the left. Various features of the semi-automatic firearm  5  are also illustrated in silhouette including a receiver  10 , a trigger  15 , a trigger guard  17 , a pistol grip  20 , and a stock  40 . 
     In various embodiments, the rapid-fire accessory  100  includes a trigger guard mount  110  for attaching the rapid-fire accessory  100  to the semi-automatic firearm  5 . In some embodiments, the trigger guard mount  110  is a forward portion of the rapid-fire accessory  100  and may include a leading edge  111  of the rapid-fire accessory  100 . An operator may secure the rapid-fire accessory  100  to the semi-automatic firearm  5  by snapping the trigger guard mount  110  onto the trigger guard  17  from a lateral side of the semi-automatic firearm  5 . The trigger guard mount  110  includes a mounting channel  115  for receiving the trigger guard  17  of the semi-automatic firearm  5 . A lateral side of the trigger guard mount  110  may be open, formed with a receiving aperture  117  through which the trigger guard  17  may be inserted into the mounting channel  115 . 
     In  FIG. 1A , the semi-automatic firearm  5  is in a ready-to-fire configuration with the trigger  15  of the semi-automatic firearm  5  in a forward position. From the ready-to-fire configuration, pulling the trigger  15  (i.e., pivoting or moving the trigger  15  rearward—toward the left as illustrated) will discharge the semi-automatic firearm  5 . In contrast in  FIG. 1B , the semi-automatic firearm  5  is in a fired configuration with the trigger  15  in a rearward position. From the loaded configuration (e.g.,  FIG. 1A ), an operator generally holds the rapid-fire accessory  100  in a relatively fixed position while pushing the semi-automatic firearm  5  forward into the fired configuration (e.g.,  FIG. 1B ), which discharges the semi-automatic firearm  5 . The operator may hold the rapid-fire accessory  100  by placing one trigger-hand finger, such as a trigger-hand middle finger, on a forward side of a lower finger grip  160  while wrapping a trigger-hand thumb around a rear side of a thumb grip  140  onto a thumb engagement surface  142 . The trigger guard  17 , when mounted in the mounting channel  115 , guides a sliding movement of the trigger guard mount  110 , and the overall rapid-fire accessory  100 , forward and rearward relative to the semi-automatic firearm  5 . At the same time, the trigger guard  17  and the overall semi-automatic firearm  5 , slide rearward and forward relative to the rapid-fire accessory. The semi-automatic firearm  5  shifts a distance T D  between the ready-to-fire configuration and the fired configuration, which corresponds to how far the trigger  15  is pulled after being reset for discharging the semi-automatic firearm  5 . 
     The rapid-fire accessory  100  also includes a trigger actuator  122  for engaging the trigger  15  of the semi-automatic firearm  5 . Fixed relative to the mounting channel  115 , the trigger actuator  122  is configured to pull the trigger  15  when the trigger guard  17  slides forward in the mounting channel  115 . In various embodiments, the trigger actuator  122  may form a forward wall of the trigger recess  120 . As illustrated in  FIG. 4D , a lower tip of the trigger  15  may be disposed in the trigger recess  120 . The trigger guard  17  sliding forward in the mounting channel  215  also means the semi-automatic firearm  5  is sliding forward relative to the rapid-fire accessory  100 . This sliding movement causes the trigger actuator  122  to engage the lower tip of the trigger  15 , pulling the trigger  15  rearward, which discharges the semi-automatic firearm  5 . Alternatively, the trigger actuator  122  may include an adjustable set-type screw for adjusting a rearward/forward position of the trigger actuator  122 . Adjustment of the rearward/forward position of the trigger actuator may be used to shorten or lengthen the distance T D  between the ready-to-fire configuration and the fired configuration. 
     With the operator continuing to hold the rapid-fire accessory  100  in a relatively fixed position, the discharge of the semi-automatic firearm  5  causes a recoil force that slides the semi-automatic firearm  5  rearward relative to the rapid-fire accessory  100 , which returns the semi-automatic firearm  5  to the ready-to-fire configuration (e.g.,  FIG. 1A ). A forward edge  144  of the thumb grip  140  may act as a stop. Once the semi-automatic firearm  5  returns to the ready-to-fire configuration, if the operator maintains a steady forward-pushing force on the semi-automatic firearm  5  relative to the rapid-fire accessory  100 , the semi-automatic firearm  5  will discharge in a rapid-fire succession like that of freehand bump fire techniques. However, unlike freehand bump fire techniques, use of the rapid-fire accessory  100  is easier to operate and does not involve elaborate and/or expensive accessories. 
       FIG. 2A  illustrates an operator  60  firing a bullet  54  from another semi-automatic firearm  6  while using the rapid-fire accessory (e.g.,  100 , which is covered by a trigger hand  80  of the operator in  FIG. 2A ), in accordance with various embodiments. The semi-automatic firearm  6  is illustrated with solid lines representing a rearward position in the ready-to-fire configuration R and with dotted lines representing a forward position in the fired configuration F. The semi-automatic firearm  6  illustrated is an AR- 15  style weapon, which includes a receiver  10 , a trigger  15  with a trigger guard  17 , a pistol grip  20 , a barrel  30  with a hand guard  32 , a stock  40  with a butt end  45 , and a magazine  52  for holding ammunition (i.e., additional cartridges). Other features common to an AR- 15  style weapon as well as other semi-automatic firearms are illustrated, including a carrying handle  12  and a front site  33 . 
     The rapid-fire accessory in accordance with various embodiments may assist the operator  60  in bump firing the semi-automatic firearm  6 . After mounting the rapid-fire accessory on the semi-automatic firearm  6 , the operator  60  may hold the semi-automatic firearm  6  away from his or her body in order to allow the weapon to recoil rearward after firing. As shown, the butt end  45  is spaced away from the operator&#39;s shoulder. Alternatively, the semi-automatic firearm  6  could be held in other positions away from the operator&#39;s body, such as down near the hip. The operator  60  places a trigger hand  80  around both the rapid-fire accessory and the pistol grip  20 . Unlike freehand bump fire techniques, the operator  60  does not need to work at maintaining the trigger hand  80  in a rigid position with a trigger finger  82  in front of the trigger  15 . The rapid-fire accessory provides the rigid positioning needed for bump firing. The operator  60  also places a forend hand  70  on the hand guard  32 . While maintaining the trigger hand  80  in a relatively fixed position the operator uses the forend hand  70  to push the hand guard  32  forward. This movement shifts the semi-automatic firearm  6  forward relative to the trigger hand  80  and the rapid-fire accessory, which causes the trigger  15  to engage the trigger actuator (e.g.,  122 ). As the trigger actuator pushes rearward on the trigger  15 , the trigger moves rearward. If the operator  60  pushes forward far enough with the forend hand  70 , the trigger actuator will pull the trigger enough to discharge the semi-automatic firearm  6 . 
     The semi-automatic firearm  6  may start in the fired configuration F when the trigger actuator pulls the trigger  15  far enough to fire the semi-automatic firearm  6 . Firing the semi-automatic firearm  6  propels the bullet  54  forward, but also causes a recoil force  50  that causes the semi-automatic firearm  6  to shift rearwards toward the operator  60 . If the operator  60  holds the trigger hand  80  rigid/firm, and thus holds the rapid-fire accessory steady, the recoil force  50  will shift the semi-automatic firearm  6  rearwards into the ready-to-fire configuration R again. A semi-automatic firearm  6  in the ready-to-fire configuration R is once again ready to be fired. Thereafter, if the operator  60  maintains a forward force on the hand guard  32  while keeping the trigger hand  80  stationary in the rigid position (i.e., pulling the forend hand  70  away from the trigger hand  80 ), the operator  60  will be able to once again push the hand guard  32  forward after the recoil force  50  dissipates, which once again discharges the semi-automatic firearm  6 . By continuously maintaining the forward force on the hand guard  32  with the trigger hand  80  held rigid/firm, the semi-automatic firearm  6  will discharge in a rapid-fire succession that is generally faster than what the operator  60  would achieve with repeated pulls of the trigger finger  82 . 
       FIGS. 2B and 2C  illustrate close-up views of the semi-automatic firearm of  FIG. 2A  in the ready-to-fire and fired configurations, respectively, using the rapid-fire accessory (e.g.,  100 ) in accordance with various embodiments.  FIGS. 2B and 2C  are similar to  FIGS. 1A and 1B , but include the forend hand  70  and the trigger hand  80  on the semi-automatic firearm  6 . 
     In  FIG. 2B , the semi-automatic firearm  6  is in the ready-to-fire configuration with the trigger  15  of the semi-automatic firearm  6  in a forward position. In contrast in  FIG. 2C , the semi-automatic firearm  6  is in a fired configuration with the trigger  15  in a rearward position. The operator (e.g.,  60 ) may hold the rapid-fire accessory mounted on the semi-automatic firearm  6  with the trigger hand  80  wrapped loosely around the pistol grip  20  and firmly around the rapid-fire accessory. Meanwhile, to use the rapid-fire accessory to bump fire the semi-automatic firearm  6 , the operator should grip the hand guard  32  with the forend hand 
     To hold the rapid-fire accessory firmly, the operator may place a trigger-hand middle finger  85  on a forward side of the lower finger grip  160  and wrap a trigger-hand thumb  86  around a rear side of the thumb grip  140 . By providing a squeezing pressure between the trigger-hand middle finger  85  and the trigger-hand thumb  86 , the operator may maintain a steady and firm grip on the rapid-fire accessory. Optionally, a trigger finger  82  may rest on an outer edge of the mounting base  150  (as illustrated) or even placed across the trigger  15 . However, when using the rapid-fire accessory of various embodiments, the operator does not need to actually touch the trigger  15  with any finger. 
     In  FIG. 2C , the semi-automatic firearm  6  is in the fired configuration. The operator may move the semi-automatic firearm  6  into the fired configuration from the ready-to-fire configuration by gripping the hand guard  32  and pulling/pushing the semi-automatic firearm  6  forward relative to the rapid-fire accessory. In doing so, the pistol grip  20  may shift forward within the trigger hand  80  the same distance T D  the rapid-fire accessory moves relative to the semi-automatic firearm  6 . 
       FIGS. 3A-3D  illustrate perspective views of the rapid-fire accessory  100  in accordance with various embodiments. The rapid-fire accessory  100  may be formed of metal, high-impact polymer, other suitable materials, or any combination thereof. The trigger guard mount  110  may be secured to or formed as an extension of the mounting base  150 . The mounting base  150  may extend rearward beyond the trigger guard mount  110  in order to provide an additional guiding surface  151  along an underside of the trigger guard and/or adjacent surfaces of the semi-automatic firearm. For example, the mounting base  150  may extend rearward further than a trailing edge  112  of the trigger guard mount  110 . 
     The trigger guard mount  110  includes a mounting channel  115  for receiving the trigger guard (e.g.,  17 ) of the semi-automatic firearm. The mounting channel  115  may be formed as a U-shaped or rectangular slot extending through the entire the trigger guard mount  110  from a leading edge  111  to a trailing edge  112 . The trigger guard mount  110  includes a receiving aperture  117 , which forms an open side of the mounting channel  115 . The trigger guard may be inserted into the mounting channel  115  through the receiving aperture  117 . Once the trigger guard is seated fully within the mounting channel  115  and upper portion of the trigger guard mount  110  will be positioned above the trigger guard and a lower portion of the trigger guard mount  110  will be positioned below the trigger guard. Once positioned inside the mounting channel  115 , the trigger guard may fit loosely therein in order to allow sliding movement between the trigger guard mount  110  and the trigger guard. A detent  118  may prevent the trigger guard from coming out of the mounting channel  115  laterally through the receiving aperture  117 . 
     The trigger guard mount  110  includes a trigger recess  120  configured to receive a lower portion of the trigger (e.g.,  15 ). Once the trigger guard mount  110  is mounted on the trigger guard, a lower portion of the trigger may be disposed in the trigger recess  120  (see,  FIG. 1A and 1B ). In addition, a forward wall of the trigger recess  120  may form the trigger actuator  122 . 
     The trigger guard mount  110  may include a trigger finger grip  132 . The trigger finger grip  132  may provide a more traditional gripping place for the trigger finger of an operator. The trigger finger grip  132  may be formed into a forward facing edge of a lateral wall that extends upward from a left lateral side of an upper portion of the trigger guard mount  110  and the mounting base  150 . Trigger finger grip  132  may be configured to align with a shape and position of the trigger once the rapid-fire accessory is mounted on the semiautomatic firearm (see,  FIG. 4D ). In this way, the operator holding the rapid-fire accessory  100  may extend a trigger finger laterally across a front of the trigger and grip the trigger finger on the trigger finger grip  132 . Depending on the design and the particular arched shape of the trigger finger grip  132 , the trigger hand finger of the operator may simultaneously engage (i.e., rest on) the trigger finger grip  132  and the trigger during bump fire sequences, the trigger will generally move in unison with the trigger finger grip  132 . 
     The trigger actuator  122  pulls the trigger. Thus, the operator need not directly engage the trigger with any finger. Optionally, and extension wall  135  may extend to the leading edge  111  of the trigger guard mount  110 . The extension wall  135  may provide an additional guide surface on a lateral side of the weapon&#39;s receiver. In addition, the extension wall  135  may prevent some operators from resting their trigger finger on the trigger, which may help train the operator not to hold the trigger finger on the trigger when bump firing. As a further alternative, the extension wall  135  may be included as a removable section, giving the operator (or owner) the option to remove or customize the extension wall  135 . 
     The rapid-fire accessory may include a lower finger grip  160  protruding from a lower portion of the trigger guard mount  110  and/or the mounting base  150 . The lower finger grip  160  may include a finger engagement surface  162 , on a forward facing side of the lower finger grip  160 . The finger engagement surface  162  may include contours designed with an ergonomic shape that allows the operator to comfortably and/or securely hold the rapid-fire accessory. For example,  FIGS. 2B and 2C  illustrate the operator holding a trigger-hand middle finger  85  on the lower finger grip  160 . 
       FIGS. 4A-4D  illustrate a front elevation, rear elevation, top plan, and right side partial section views, respectively, of a partially formed rapid-fire accessory  101  in accordance with various embodiments. 
     The rapid-fire accessory  100  described above with reference to  FIGS. 1A-2C  may formed by and/or include all or most of the features described herein with regard to the partially formed rapid-fire accessory  101 . Thus, the description herein of the partially formed rapid-fire accessory  101  and components thereof may apply to corresponding components of the rapid-fire accessory  100 . The partially formed rapid-fire accessory  101 , like the rapid-fire accessory  100 , includes a trigger guard mount  110 , a trigger actuator  122 , an extension member  130 , a mounting base  150 , and a lower finger grip  160 , further details of which are described below. 
     In  FIGS. 4A-4D , the partially formed rapid-fire accessory  101  includes an unfinished thumb grip section  141 , which is formed as a planar end portion of an extension member  130  that extends from the trigger guard mount  110 . The unfinished thumb grip section  141  may be formed as an intermediate step in forming a thumb grip (e.g.,  140 ) that is contoured for engagement with a trigger-hand thumb (e.g.,  86 ). For example, the partially formed rapid-fire accessory  101  may be formed by molding, 3-D printing, and/or an assembly of separate parts. Subsequent to forming/assembling the partially formed rapid-fire accessory  101 , the unfinished thumb grip section  141  may be altered to create a thumb grip (e.g.,  140 ) with a thumb engagement surface (e.g.,  142 ). The alterations of the unfinished thumb grip section  141  may be performed as part of manufacturing or left for an end-user and/or operator. Thus, the partially formed rapid-fire accessory  101  may be provided with an unfinished thumb grip section  141  for an end-user and/or operator to custom mold for their particular semi-automatic firearm. 
     Some elements of the mounting channel  115  are visible in  FIGS. 4A, 4B , and  4 D. In particular, a full extent of the mounting channel  115  is illustrated, which extends through the entire the trigger guard mount  110  from the leading edge  111  toward the rear of the partially formed rapid-fire accessory  101 . The mounting channel  115  may be formed with a lower wall  171 , and upper wall  173  opposed to the lower wall  171 , and a lateral wall  172  connecting the lower wall  171  and the upper wall  173  (see,  FIG. 4B ).  FIG. 4D  illustrates that when the trigger guard  17  is mounted in the mounting channel  115  (i.e., fully inserted in the mounting channel), the upper wall  173  is disposed between a bottom of the trigger  15  and the trigger guard  17 . In addition, the mounting channel  115  may be sized slightly larger than the trigger guard  17  to allow the trigger guard  17  to slide forward and rearward therein. In this way, when the trigger guard mount  110  and the trigger guard  17  move relative to one another, the trigger guard  17  may be in sliding engagement with at least one of the lower wall  171  and the upper wall  173  during the sliding movement. 
     The mounting channel  115  may include a receiving aperture  117  for inserting the trigger guard in the mounting channel  115 .  FIG. 4A  illustrates the trigger guard  17  (shown in phantom lines with gray fill) partially inserted in the mounting channel  115 . The receiving aperture  117  may be formed as a narrow slit extending the length of the mounting channel  115 . The receiving aperture  117  may be narrower than a thickness of the trigger guard  17 . Thus, a portion of the trigger guard mount  110  must be moved from an initial position, such as by slightly flexing a portion of the trigger guard mount in order to increase a width of the receiving aperture  117  enough to allow the trigger guard to be inserted into the mounting channel  115  through the receiving aperture  117 . For example,  FIG. 4A  illustrates an upper portion of the trigger guard mount  110  being flexed upward with a portion of the trigger guard  17  being inserted into the mounting channel  115 . Similarly, once the trigger guard is seated fully within the mounting channel  115 , a portion of the trigger guard mount  110  may once again be flexed upward to increase the width of the receiving aperture  117  enough to release and/or remove the trigger guard  17  from the mounting channel  115 . 
     The trigger guard mount  110  may include a detent  118  that protrudes across a portion of the receiving aperture  117  for trapping the trigger guard in the mounting channel In various embodiments, the detent  118  extends the full length of the mounting channel  115 , but the detent  118  may be shorter or longer than the full extent of the mounting channel  115 . Thus, the detent  118  may be moved, as part of flexing the portion of the trigger guard mount  110  from the initial position, in order to enable the trigger guard  17  to be inserted in the mounting channel  115 . 
     Alternatively, other means for trapping the trigger guard in the mounting channel  115  may be provided. Rather than a fixed structure like the detent  118 , a retractable detent may be provided. For example, a retractable detent may be formed as a ball bearing or pin supported from below by a compressible spring. A retractable detent may thus selectively trap the trigger guard until sufficient pressure lowers or moves aside the retractable detent for releasing the trigger guard from the mounting channel  115 . As a further example, a releasable clasp, pivotal latch, or other adjustable structure may be provided that may temporarily block all or a portion of the receiving aperture  117  to selectively trap/release the trigger guard in/from the mounting channel  115 . 
       FIGS. 5A and 5B  illustrate the rapid-fire accessory  100  partially mounted onto the semi-automatic firearm  5 . To install the rapid-fire accessory  100  on the semi-automatic firearm  5 , an operator or other individual may align the receiving aperture  117  of the rapid-fire accessory  100  with the trigger guard  17  of the semi-automatic firearm  5 . Once properly positioned, pressing the trigger guard mount  110  into the trigger guard  17  may expand the receiving aperture  117 , at least until the trigger guard  17  clears the detent (e.g.,  118 ). It may be helpful to first insert a right leading edge corner of the trigger guard mount  110  onto the trigger guard  17 . Once the trigger guard  17  is at least partially inserted into the mounting channel (e.g.,  115 ), the operator or other individual may pivot the thumb grip  140  (i.e., the rear portion of the rapid-fire accessory  100 ) toward the pistol grip  20  until the thumb grip  140  is positioned rearward of the pistol grip  20 . 
     Some elements of the thumb grip  140  and the thumb engagement surface  142  are visible in  FIGS. 5A and 5B . In particular, the extension member  130  extends rearward from a lateral side of the trigger guard mount  110  and connects the thumb grip  140  to the trigger guard mount  110  and/or the mounting base  150 . The thumb grip  140  may be molded and/or formed to wrap around a rear upper side of the pistol grip  20 . In this way, the extension member  130  extends rearward away from the trigger actuator  122 , placing the thumb grip  140  on the backside of the pistol grip  20 , which is remote from the trigger guard mount  110 . In addition, the thumb grip  140  may include a contoured rear surface that forms the thumb engagement surface  142 . The thumb engagement surface  142  is thus configured to engage the operator&#39;s trigger-hand thumb (e.g.,  86 ), particularly while the operator is firing the semi-automatic firearm  5 . As shown in  FIGS. 3A, 3C, and 5A , the thumb engagement surface  142  may be ergonomically contoured for comfortable and/or secure engagement by an appropriate portion of the trigger-hand thumb. Alternatively, the thumb engagement surface  142  may be flat, have a different contour, or a different shape. 
       FIGS. 6A-6C  illustrate a rapid-fire accessory  200  used with a semi-automatic firearm  3 , with a conventional rifle stock (rifle without an adjustable butt stock and pistol grip), in accordance with various embodiments.  FIG. 6A  illustrates a central portion of the semi-automatic firearm  3  with the rapid-fire accessory  200  separate there from.  FIG. 6B  illustrates the semi-automatic firearm  3  of  FIG. 6A  in a ready-to-fire configuration with the rapid-fire accessory  200  mounted thereon.  FIG. 6C  illustrates the semi-automatic firearm  3  of  FIG. 6A  in a fired configuration with the rapid-fire accessory  200  mounted thereon. In the orientations illustrated in  6 A- 6 C, the semi-automatic firearm  3  is aiming to the right, which is referred to herein as a “forward” direction, which is opposed to a “rearward” direction aiming to the left, as illustrated. Various features of the semi-automatic firearm  3  are also illustrated including a trigger  15  and a trigger guard  17 . 
     In various embodiments, the rapid-fire accessory  200  includes a trigger guard mount  210  for attaching the rapid-fire accessory  200  to the semi-automatic firearm  3 . In some embodiments, the trigger guard mount  210  is a central portion of the rapid-fire accessory  200 . An operator may secure the rapid-fire accessory  200  to the semi-automatic firearm  3  by fitting the trigger guard mount  210  onto the trigger guard  17  from a bottom side of the semi-automatic firearm  3 . The trigger guard mount  210  includes a mounting channel  215  for receiving the trigger guard  17  of the semi-automatic firearm  3 . An upper side of the trigger guard mount  210  is open, formed with a receiving aperture  217  through which the trigger guard  17  may be inserted into the mounting channel  215 . 
     In  FIG. 6B , the semi-automatic firearm  3  is in a ready-to-fire configuration with the trigger  15  of the semi-automatic firearm  3  in a forward position. From the ready-to-fire configuration, pulling the trigger  15  (i.e., pivoting or moving the trigger  15  rearward—toward the left as illustrated) will discharge the semi-automatic firearm  3 . In contrast in  FIG. 6C , the semi-automatic firearm  3  is in a fired configuration with the trigger  15  in a rearward position. From the ready-to-fire configuration (e.g.,  FIG. 6B ), an operator generally holds the rapid-fire accessory  200  in a relatively fixed position while pushing the semi-automatic firearm  3  forward into the firing configuration (e.g.,  FIG. 6C ), which discharges the semi-automatic firearm  3 . The operator may hold the rapid-fire accessory  200  by placing one trigger-hand finger, such as a trigger-hand middle finger, on a forward side of a lower finger grip  260  while wrapping a trigger-hand thumb around a rear side of a thumb grip  240  onto a thumb engagement surface  242 . 
     The trigger guard  17 , when mounted in the mounting channel  215 , guides a sliding movement of the trigger guard mount  210 , and the overall rapid-fire accessory  200 , forward and rearward relative to the semi-automatic firearm  3 . The trigger guard  17  may be in sliding engagement with a lower wall  272  (see,  FIGS. 6A and 7C ) of the mounting channel  215  during the forward and/or rearward movement. In addition, as the trigger guard  17  moves relative to the mounting channel  215 , the overall semi-automatic firearm  3  moves relative to the rapid-fire accessory  200 . The semi-automatic firearm  3  shifts a distance S D  between the ready-to-fire configuration and the firing configuration, which may be equal to or slightly further than the distance the trigger  15  is pulled after being reset for discharging the semi-automatic firearm  3 . 
     The rapid-fire accessory  200  may additionally include supplemental sliding engagement surfaces  281 . The supplemental sliding engagement surfaces  281  may stabilize the sliding movement of the rapid-fire accessory  200 , which may otherwise pitch and/or twist retarding movement relative to the trigger guard  17 . The supplemental sliding engagement surfaces  281  may be configured to slide along a linear surface  11  of the semi-automatic firearm  3 . Optionally, the supplemental sliding engagement surfaces  281  may extend from other parts of the rapid-fire accessory for engaging and sliding along other surfaces of the semi-automatic firearm  3 . In addition, additional supplemental sliding engagement surfaces  281  may be provided. 
     The rapid-fire accessory  200  also includes a trigger actuator  222  for engaging the trigger  15  of the semi-automatic firearm  3 . Fixed relative to the mounting channel  215 , the trigger actuator  222  is configured to pull the trigger  15  when the trigger guard  17  slides forward in the mounting channel  215 . In various embodiments, the trigger actuator  222  may include a pin or other structure that extends laterally across the mounting channel. As illustrated in  FIG. 6C , a lower tip of the trigger  15  may be disposed in the mounting channel and/or rearward of the trigger actuator  222 . The trigger guard  17  sliding forward in the mounting channel  215  also means the semi-automatic firearm  3  is sliding forward relative to the rapid-fire accessory  200 . This sliding movement causes the trigger actuator  222  to engage the lower tip of the trigger  15 , pulling the trigger  15  rearward, which discharges the semi-automatic firearm  3 . With the operator continuing to hold the rapid-fire accessory  200  in a relatively fixed position, the discharge of the semi-automatic firearm  3  causes a recoil force that moves the semi-automatic firearm  3  rearward relative to the rapid-fire accessory  200 , which returns the semi-automatic firearm  3  to the loaded configuration (e.g.,  FIG. 6B ). 
     A rear wall  275  of the mounting channel  215  may act as a stop, preventing further rearward relative movement of the trigger guard  17  relative to the rapid-fire accessory  200 . Engagement of the trigger guard  17  with the rear wall  275  may also coincide with the semi-automatic firearm  3  being in the ready-to-fire configuration, which automatically rechambers another cartridge into the weapon. Thereafter, if the operator maintains a forward force on the hand guard of the semi-automatic firearm  3 , while keeping the trigger hand stationary (i.e., pulling the forend hand away from the trigger hand), the operator will be able to once again push the semi-automatic firearm  3  forward after the recoil force dissipates, which once again discharges the semi-automatic firearm  3  once the firing configuration is reached. A forward wall  277  of the mounting channel  215  may act as a forward stop, preventing further forward relative movement of the trigger guard  17  relative to the rapid-fire accessory  200 . By continuously maintaining the forward force on the hand guard with the trigger hand held steady, the semi-automatic firearm  3  will discharge in a rapid-fire succession like that of freehand bump fire techniques. However, unlike freehand bump fire techniques, use of the rapid-fire accessory  200  is easier to learn and does not involve elaborate and/or expensive accessories. 
       FIGS. 7A-7D  illustrate the rapid-fire accessory  200  in accordance with various embodiments. Some elements of the thumb grip  240  and the thumb engagement surface  242  are visible in  FIGS. 7A, 7B, and 7D . In particular, a rearward portion of the trigger guard mount  210  may include a downward protruding horn that together with an outside of the rear wall  275  forms the thumb grip  240 . In this way, the thumb grip  240  may be disposed rearward from the trigger actuator  222 . The thumb grip  240  may be molded and/or formed to include a contoured rear surface that forms the thumb engagement surface  242 . The thumb engagement surface  242  is thus configured to engage the operator&#39;s trigger-hand thumb (e.g.,  86 ), particularly while the operator is firing the semi-automatic firearm  3 . As shown in  FIGS. 7A, 7B, and 7D , the thumb engagement surface  242  may be ergonomically contoured for comfortable and/or secure engagement by an appropriate portion of the trigger-hand thumb. Alternatively, the thumb engagement surface  242  may be flat, have a different contour, or a different shape. 
     The rapid-fire accessory  200  may include a lower finger grip  260  protruding from a lower forward portion of the trigger guard mount  210 . The lower finger grip  260  may include a finger engagement surface  262 , on a forward facing side of the lower finger grip  260 . The finger engagement surface  262  may include contours designed with an ergonomic shape that allows the operator to comfortably and/or securely hold the rapid-fire accessory  200 . 
     The rapid-fire accessory  200  may include a trigger finger grip  232 . The trigger finger grip  232  may provide a gripping place for the trigger finger of the operator, which is forward of the more conventional trigger hand finger position on the trigger. The trigger finger grip  232  may be formed on an outside of the forward wall  277 , which places the trigger finger grip  232  at an opposite end of the mounting channel  215  from the thumb grip  240 . The trigger finger grip  232  may be disposed forward of the trigger actuator  222 . Thus, using all the grip surfaces included on the rapid-fire accessory  200 , the operator may simultaneously place a trigger-hand thumb on the thumb grip  240 , a trigger-hand middle finger on the lower finger grip  260 , and a trigger hand finger on the trigger finger grip  232 . 
     Some elements of the mounting channel  215  are visible in  FIG. 7C . In particular, the mounting channel  215  includes a right wall  271 , a left wall  273  opposed to the right wall  271 , and a lower wall  272  connecting the right wall  271  to the left wall  273 . In addition, the mounting channel  215  extends from the rear wall  275  to the forward wall  277  opposed to the rear wall  275 . Once mounted in the mounting channel  215 , the trigger guard may slide along the lower wall  272  during sliding movements. 
       FIG. 7C  also shows the trigger actuator  222  extending from the right wall  271  to the left wall  273 . The trigger actuator  222  may be a removably secured element (e.g., a locking bar or pin) held in a pair of apertures  223 . The trigger actuator  222  may be pressure-fit in one or both of the apertures  223 . Additionally or alternatively, the trigger actuator  222  may be formed as a double-sided screw with larger screw heads engaging the right and left walls  271 ,  273 . A first aperture  223  may be disposed in the right wall  271  and a second aperture  223  may be disposed opposite the first aperture in the left wall  273 . The trigger actuator  222  may be removed in order to allow the trigger guard to be fully seated within the mounting channel  215 . Once the trigger guard is fully seated in the mounting channel  215 , the trigger actuator  222  inserted into the apertures  223  may extend across the mounting channel  215  from the right wall  271  to the left wall  273 . In addition, once the trigger guard is fully seated in the mounting channel  215 , the trigger guard may be disposed between the trigger actuator  222  and the lower wall  272 . 
     The trigger actuator  222  may be held in-place in the apertures  223  through a simple friction fit. Further still, the trigger actuator  222  may be formed as a push button pin or other quick release pin. Alternatively, further fixation elements may be provided on or with the trigger actuator  222  such as a hair pin style locking pin, a ball lock pin, or double ball detent pins. Thus, the trigger actuator  222  may be removably secured to at least one of the right wall  271  and the left wall  273 . In addition, removal of the trigger actuator  222  releases the trigger guard from the mounting channel  215 . 
     The foregoing descriptions are provided merely as illustrative examples and are not intended to require or imply that the elements of various embodiments are required. Further, any reference to claim elements in the singular, for example, using the articles “a,” “an” or “the” is not to be construed as limiting the element to the singular. 
     While the terms such as “first” and “second” are used herein to describe similarly named elements, such identifiers are merely for convenience and are not meant to limit various embodiments to a particular order, sequence, type of network or carrier. 
     The rapid-fire accessory in accordance with various embodiments provides an easy-to-use device that may enable an operator to bump fire a semi-automatic firearm more easily than free hand techniques. In addition, the rapid-fire accessory in accordance with various embodiments does not demand significant modification of the semi-automatic firearm, such as replacement of the pistol grip, stock, and/or other elements. In this way, users may keep their favorite original, replacement, or aftermarket stock and/or pistol grip. The rapid-fire accessory in accordance with various embodiments is also quick and easy to install without requiring special tools. Further, the rapid-fire accessory in accordance with various embodiments is not bulky, is relative small, and may be manufactured relatively inexpensively. 
     The preceding description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the following claims and the principles and novel features disclosed herein.