Patent Publication Number: US-11035636-B2

Title: Shotgun ammunition feeding system

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims benefit of priority to U.S. Provisional Application No. 62/878,826, filed Jul. 26, 2019, and U.S. Provisional Application No. 62/899,425, filed Sep. 12, 2019, both of which are hereby incorporated by reference herein in their entirety. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to ammunition feeding systems for shotguns having multiple magazines. 
     BACKGROUND 
     Shotguns for self-defense purposes may feature dual magazine tubes which provide expanded ammunition capacity. A desirable feature in such shotguns allows the operator to manually select the tube from which the ammunition feeds. For pump action operation, the action must reciprocate from battery to open breech and back into battery to the full extent of fore-end travel for proper operation of the feed system, which moves a shell from one of the magazines into the chamber. A manually operated selector is used to select the magazine tube from which the shell is removed and chambered. 
     If the magazine selector is manipulated during fore-end travel into battery before the return of the fore-end to the full extent of travel it may cause shells to be released from both magazine tubes simultaneously. The result will be a malfunction (known as “locking up”) of the action. A mechanism which prevents the manipulation of the magazine selector in any position but at the full extent of fore-end travel is expected to avoid this malfunction. 
     SUMMARY 
     The invention concerns a feeding system for feeding ammunition to a firearm such as a shotgun. In an example embodiment the feeding system comprises a right magazine tube mountable on the firearm. The right magazine tube defines a right bore for receiving the ammunition. A right outer cut-off is mountable on the firearm. The right outer cut-off has a right blocking surface movable between a first position blocking the right bore and a second position not blocking the right bore. A right biasing spring acts on the right outer cut-off and biases the right blocking surface into the first position. A right cam follower is mounted on the right outer cut-off. A right cam is mountable on the firearm. The right cam is engageable with the right cam follower for moving the right blocking surface between the first and the second positions. A left magazine tube is mountable on the firearm. The left magazine tube defines a left bore for receiving the ammunition. A left outer cut-off is mountable on the firearm. The left outer cut-off has a left blocking surface movable between a first position blocking the left bore and a second position not blocking the left bore. A left biasing spring acts on the left outer cut-off and biases the left blocking surface into the first position. A left cam follower is mounted on the left outer cut-off. A left cam is mountable on the firearm. The left cam is engageable with the left cam follower for moving the left blocking surface between the first and the second positions. 
     A selector is mountable on the firearm. The selector has an activation surface in facing relation with the right and left cams. The selector is movable lengthwise along the first and second magazine tubes for engaging the activation surface with one of the left or right cams. The selector is movable transversely to the first and second magazine tubes for positioning the activation surface for engagement with one of the left or right cams. 
     An example feeding system according to the invention may further comprise an interrupter surface mountable on the firearm. An example interrupter surface extends lengthwise along the first and second magazine tubes. The interrupter surface has an end positioned distal to the right and left outer cut-offs. A boss extends from the selector. The boss is engageable with the interrupter surface when the selector is positioned between the end and the right and left outer cut-offs thereby preventing movement of the selector transversely to the right and left magazine tubes. 
     An example feeding system may further comprise an inner cut-off mountable on the firearm. An example inner cut-off has first and second blocking surfaces movable between a first position respectively blocking the right and the left bores, and a second position not blocking the right and left bores. An inner cam follower is mounted on the inner cut-off. An inner cut-off cam is mountable on the firearm in an example. The inner cut-off cam is engageable with the inner cam follower for moving the first and second blocking surfaces between the first and second positions. An inner cut-off cam actuator is movably mountable on the firearm by way of example. The inner cut-off cam actuator is movable into engagement with the inner cut-off cam for moving the first and second blocking surfaces between the first and second positions. An inner biasing spring acts on the inner cut-off and biasing the first and second blocking surfaces into the second position. 
     In an example feeding system the inner cut-off comprises a housing mountable on the magazine tubes. A lever is mounted on the housing and pivotable about an axis oriented transversely to the magazine tubes. Further by way of example, a feeding system may comprise a fore-end chassis mountable on the firearm and movable lengthwise along the right and left magazine tubes. The selector and the inner cut-off cam actuator are mounted on the fore-end chassis in this example. 
     In a particular example embodiment the right outer cut-off comprises a right lever pivotably mountable on the right magazine tube. The right blocking surface is mounted on one end of the right lever. The right cam follower is mounted on an opposite end of the right lever. Further by way of example, the left outer cut-off comprises a left lever pivotably mountable on the left magazine tube. The left blocking surface is mounted on one end of the left lever. The left cam follower is mounted on an opposite end of the left lever. By way of example, the right cam may comprise an elongate body slideably mountable on the right magazine tube and the left cam may comprise an elongate body slideably mountable on the left magazine tube. 
     In an example embodiment of a feeding system the selector may comprise a body mounted on the fore-end chassis and movable relatively thereto transversely to the right and left magazine tubes. The activation surface and the boss are mounted on the body. A right button projects from one side of the body transversely to the right and left magazine tubes. A left button projects from an opposite side of the body transversely to the right and left magazine tubes. The right and left buttons are adapted for manually moving the body transversely to the right and left magazine tubes. 
     In a particular example embodiment the interrupter surface comprises a wall mountable between the left and right magazine tubes. Further by way of example the right outer cut-off may comprise a right manual actuator surface extending therefrom and the left outer cut-off may comprise a left manual actuator surface extending therefrom. The right and left manual actuator surfaces permit manual moving of the right and left blocking surfaces between the first and second positions. 
     The invention also encompasses a shotgun. In an example embodiment the shotgun comprises a receiver. A barrel having a breech and a chamber is mounted on the receiver. A feeding system for feeding ammunition to the chamber is also provided. An example feeding system comprises a right magazine tube mounted on the receiver. The right magazine tube defines a right bore for receiving the ammunition. A right outer cut-off is mounted on the receiver. The right outer cut-off has a right blocking surface movable between a first position blocking the right bore and a second position not blocking the right bore. A right biasing spring acts on the right outer cut-off for biasing the right blocking surface into the first position. A right cam follower is mounted on the right outer cut-off. A right cam is mounted on the receiver. The right cam is engageable with the right cam follower for moving the right outer cut-off between the first and the second positions. A left magazine tube is mounted on the receiver. The left magazine tube defines a left bore for receiving the ammunition. A left outer cut-off is mounted on the receiver. The left outer cut-off has a left blocking surface movable between a first position blocking the left bore and a second position not blocking the left bore. A left biasing spring acts on the left outer cut-off for biasing the left blocking surface into the first position. A left cam follower is mounted on the left outer cut-off. A left cam is mounted on the receiver. The left cam is engageable with the left cam follower for moving the left blocking surface between the first and the second positions. A selector is mounted on the receiver. The selector has an activation surface in facing relation with the right and left cams. The selector is movable lengthwise along the first and second magazine tubes for engaging the activation surface with one of the left or right cams. The selector is movable transversely to the first and second magazine tubes for positioning the activation surface for engagement with one of the left or right cams. 
     By way of example a shotgun according to the invention may further comprise an interrupter surface mounted on the receiver. An example interrupter surface may extend lengthwise along the first and second magazine tubes. The interrupter surface has an end positioned distal to the right and left outer cut-offs. A boss extends from the selector. The boss is engageable with the interrupter surface when the selector is positioned between the end and the right and left outer cut-offs thereby preventing movement of the selector transversely to the right and left magazine tubes. 
     An example shotgun may further comprise an inner cut-off mounted on the receiver. An example inner cut-off may have first and second blocking surfaces movable between a first position respectively blocking the right and the left bores, and a second position not blocking the right and left bores. An inner cam follower is mounted on the inner cut-off. An inner cut-off cam is mountable on the shotgun. The inner cut-off cam is engageable with the inner cam follower for moving the first and second blocking surfaces between the first and second positions. An inner cut-off cam actuator may be movably mounted on the receiver. The inner cut-off cam actuator is movable into engagement with the inner cut-off cam for moving the first and second blocking surfaces between the first and second positions. An inner biasing spring acts on the inner cut-off and biases the first and second blocking surfaces into the second position. 
     An example the inner cut-off may comprise a housing mounted on the magazine tubes. A lever is mounted on the housing and is pivotable about an axis oriented transversely to the magazine tubes in this example. 
     A shotgun according to the invention may further comprise a fore-end chassis mounted on the receiver. The fore-end chassis is movable lengthwise along the right and left magazine tubes. The selector and the inner cut-off cam actuator are mounted on the fore-end chassis. 
     In an example embodiment the right outer cut-off may comprise a right lever pivotably mounted on the right magazine tube. The right blocking surface is mounted on one end of the right lever, and the right cam follower is mounted on an opposite end of the right lever in this embodiment. 
     In an example embodiment, the left outer cut-off comprises a left lever pivotably mounted on the left magazine tube. The left blocking surface is mounted on one end of the left lever, and the left cam follower is mounted on an opposite end of the left lever. 
     In a specific example embodiment the right cam comprises an elongate body slidably mounted on the right magazine tube. Also by way of example, the left cam comprises an elongate body slidably mounted on the left magazine tube. In an example embodiment the selector may comprise a body mounted on the fore-end chassis. The body is movable relatively to the fore-end chassis transversely to the right and left magazine tubes. The activation surface and the boss may be mounted on the body. A right button projects from one side of the body transversely to the right and left magazine tubes. A left button projects from an opposite side of the body transversely to the right and left magazine tubes. The right and left buttons are adapted for manually moving the body transversely to the right and left magazine tubes. 
     In an example embodiment the interrupter surface may comprise a wall mounted on the receiver between the left and right magazine tubes. Further by way of example the right outer cut-off may comprise a right manual actuator surface extending therefrom, and the left outer cut-off may comprise a left manual actuator surface extending therefrom. The right and left manual actuator surfaces permit manual moving of the right and left blocking surfaces between the first and second positions in this example. 
     The invention further encompasses a selector mountable on a shotgun having a plurality of ammunition magazines wherein respective cams for releasing the ammunition from the magazines are associated with each magazine. In an example embodiment the selector comprises a selector body defining an activation surface positionable in facing relation with the cams one at a time. The selector body is mountable on the shotgun and movable relatively to the cams for engaging the activation surface with a selected one of the cams. In a particular example the selector body is movable transversely to the magazines for positioning the activation surface in facing relation with the selected one of the cams. The selector body may also be movable lengthwise along the magazines for engagement of the activation surface with the selected one of the cams. 
     A selector according to the invention may further comprise an interrupter surface mountable on the shotgun. The interrupter surface may extend lengthwise along the magazines and have an end positionable distal to the cams. A boss extends from the selector. The boss is engageable with the interrupter surface when the selector is positioned between the end and the cams thereby preventing movement of the selector transversely to the magazines. 
     The invention also includes shotgun, which, by way of example comprises a plurality of ammunition magazines and respective cams for releasing ammunition from the magazines associated with each cam. The example shotgun may also comprise a selector. In a specific example the selector comprises a selector body mounted on the shotgun. The selector body defines an activation surface positionable in facing relation with the cams one at a time. The selector body is movable relatively to the cams for engaging the activation surface with a selected one of the cams. 
     By way of example the selector body is movable transversely to the magazines for positioning the activation surface in facing relation with a selected one of the cams. Further by way of example, the selector body may be movable lengthwise along the magazines for engagement of the activation surface with a selected one of the cams. An example shotgun may further comprise an interrupter surface mounted on the shotgun. The interrupter surface may extend lengthwise along the magazines in an example embodiment and have an end positionable distal to the cams. A boss extends from the selector. The boss is engageable with the interrupter surface when the selector is positioned between the end and the cams to thereby prevent movement of the selector transversely to the magazines. A further example comprises a fore-end chassis movably mounted thereon. The selector body is mounted on the fore-end chassis in this example. The example shotgun may also include an action. The fore-end chassis is connected to the action, such that motion of the fore-end chassis cycles the action into and out of battery during operation of the shotgun. 
     An example shotgun according to the invention may comprise a plurality of ammunition magazines and respective cut-offs for releasing ammunition from the magazines associated with each cut-off. Each of the cut-offs has a blocking surface movable between a first position blocking one of the magazines and a second position not blocking the one of the magazines. At least one of the cut-offs has a manual actuator surface extending therefrom. The manual actuator surface permits manual moving of the blocking surface of the at least one cut-off between the first and second positions. In an example shotgun according to the invention the at least one cut-off may comprise a lever pivotably mounted on one of the magazines. The blocking surface of the at least one cut-off is mounted proximate to one end of the lever. The manual actuator surface is mounted proximate to an opposite end of the lever in this example. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a shotgun having an example ammunition feeding system according to the invention; 
         FIG. 2  is an isometric view of a portion of the receiver of the shotgun shown in  FIG. 1 ; 
         FIGS. 3 and 3A  are isometric views of components used in an example outer cut-off according to the invention; 
         FIG. 4  is an isometric view of an example inner cut-off mechanism according to the invention; 
         FIGS. 5-9  are isometric views illustrating operation of an example feeding mechanism according to the invention; 
         FIG. 9A  is a side view of a component part of the example feeding mechanism according to the invention; 
         FIG. 10  is an isometric view of a portion of the receiver of the shotgun shown in  FIG. 1  illustrating an example magazine selector according to the invention; 
         FIG. 11  is a top view of an example selector interrupter according to the invention; and 
         FIG. 12  is a side view of a portion of the selector interrupter shown in  FIG. 11 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a firearm, in this example a self-defense shotgun  10  according to the invention. Shotgun  10  comprises a receiver  12  which houses a fire control group  14 . As also shown in  FIG. 2 , a barrel  16  is mounted on receiver  12 , the barrel having a chamber  18  and breech  20 , the breech being opened and closed by a breech block (not shown) movable into and out of battery. A feeding system  24  for feeding ammunition to the chamber  18  is also mounted on the receiver  12 . 
       FIG. 2  shows an example feeding system  24  according to the invention. Example feeding system  24  comprises a right magazine tube  26  mounted on the receiver  12 , the right magazine tube defining a right bore  28  for receiving the ammunition  30  (see  FIG. 5 ). A right outer cut-off  32  is mounted on the receiver  12 . In this example, the right outer cut-off  32  is mounted directly on the right magazine tube  26  and thus indirectly mounted on receiver  12 . As shown in  FIG. 5 , the right outer cut-off  32  comprises a right lever  34  mounted within a channel  36  defined by two sidewalls  38  projecting from the right magazine tube  26 . As shown in  FIG. 3 , right lever  34  is pivotable about an axis  40  oriented transversely to the right magazine tube  26 . A right blocking surface  42  is mounted on one end of the right lever  34 , and a right cam follower  44  is mounted on an opposite end of the right lever. Upon pivoting motion of the right lever  34  about axis  40 , the right blocking surface  42  is movable between a first position, shown in  FIG. 5 , blocking the right bore  28  of the right magazine tube  26 , and a second position, shown in  FIG. 7 , not blocking the right bore. When in the first position, shown in  FIG. 5 , the right outer cut-off  32  engages and retains ammunition  30  within the right magazine tube  26 ; when in the second position, shown in  FIG. 7 , the right outer cut-off  32  permits the ammunition to be released from the right magazine tube  26 . As is well understood, individual rounds of ammunition are biased toward the right blocking surface  42  by a spring (not shown) within the magazine tube. As shown in  FIGS. 3 and 5 , a right biasing spring  46  acts on the right outer cut-off  32  for biasing the right blocking surface  42  into the first position. However, the right outer cut-off  32  further comprises a right manual actuator surface  48 . As shown in  FIG. 1 , the right manual actuator surface  48  extends from the right lever  34  and projects proud of the receiver  12 . This configuration permits ready manual access to the right outer cut-off  32  which may thus be pivoted between the first and second positions to release rounds of ammunition  30  from the right magazine tube  26  without cycling the action of the shotgun  10  as described below. 
       FIGS. 3 and 5  also show the right cam follower  44  mounted on the right outer cut-off  32 . In this example, the right cam follower  44  comprises an angularly oriented right ramp surface  50  which interfaces with a right cam  52  also mounted on the receiver  12 . As shown in  FIGS. 3 and 5 , the right cam  52  comprises an elongate body  54  slidably mounted within the channel  36  on the right magazine tube  26 . One end of body  54  comprises a complementary ramp surface  56  which engages the right ramp surface  50  of lever  34 . Engagement between the angularly oriented ramp surfaces  50  and  56  permits sliding motion of the right cam  52  toward the right outer cut-off to pivot the right outer cut-off clockwise (as seen in the figures) from the first to the second position to release a round of ammunition  30  from the right magazine tube  26  (compare  FIGS. 5 and 7 ). The right biasing spring  46  pivots the right outer cut-off  32  counterclockwise and back into the second (blocking) position when force is no longer applied to the right cam  52 . A return spring  53 , positioned within the elongate body  54 , acts between the elongate body and a pin  55  fixed within the channel  36  (see  FIG. 5 ) to force the right cam  52  away from the right outer cut-off  32  when force is no longer applied to the right cam. 
     As shotgun  10  is a self-defense shotgun, its feeding system  24  coordinates the feeding of ammunition  30  to the chamber  18  from either the right magazine tube  26  or a left magazine tube  58  shown in  FIG. 2 .  FIGS. 10 and 11  show the example feeding system  24  comprising the left magazine tube  58  mounted on the receiver  12 . The left magazine tube  58  defines a left bore  60  for receiving the ammunition  30  (see  FIG. 11 ). A left outer cut-off  62  is mounted on the receiver  12 . In this example, the left outer cut-off  62  is mounted directly on the left magazine tube  58  and is thus indirectly mounted on receiver  12 . As shown in  FIGS. 3A and 11 , the left outer cut-off  62  comprises a left lever  64  mounted within a channel  66  defined by two sidewalls  68  projecting from the left magazine tube  58 . Left lever  64  is pivotable about an axis  70  oriented transversely to the left magazine tube  58 . A left blocking surface  72  is mounted on one end of the left lever  64 , and a left cam follower  74  is mounted on an opposite end of the left lever. Similar to the right lever, pivoting motion of the left lever  64  about its axis  70  moves the left blocking surface  72  between a first position blocking the left bore  60  of the left magazine tube  58 , and a second position, not blocking the left bore. When in the first position, the left outer cut-off  62  engages and retains ammunition  30  within the left magazine tube  58 ; when in the second position, the left outer cut-off  62  permits the ammunition to be released from the left magazine tube  58 . As is well understood, individual rounds of ammunition are biased toward the left blocking surface  72  by a spring (not shown) within the left magazine tube. As shown in  FIGS. 3A and 11 , a left biasing spring  76  acts on the left outer cut-off  62  for biasing the left blocking surface  72  into the first position. However, the left outer cut-off  62  further comprises a left manual actuator surface  78 . Similar to the right manual actuator surface  48  shown in  FIG. 1 , the left manual actuator surface  78  extends from the left lever  64  and also projects proud of the receiver  12 . This configuration permits ready manual access to the left outer cut-off  62  which may thus be pivoted between the first and second positions to release rounds of ammunition  30  from the left magazine tube  58  without cycling the action of the shotgun  10  as described below. 
       FIGS. 3A and 11  also show the left cam follower  74  mounted on the left outer cut-off  62 . In this example, the left cam follower  74  comprises an angularly oriented left ramp surface  80  which interfaces with a left cam  82  also mounted on the receiver  12 . As shown in  FIGS. 3A and 11 , the left cam  82  comprises an elongate body  84  slidably mounted within the channel  66  on the left magazine tube  58 . One end of body  84  comprises a complementary ramp surface  86  which engages the left ramp surface  80 . Engagement between the angularly oriented ramp surfaces  80  and  86  permits sliding motion of the left cam  82  toward the left outer cut-off  62  to pivot the left outer cut-off from the first to the second position to release a round of ammunition  30  from the left magazine tube  58 . The left biasing spring  76  pivots the left outer cut-off  62  counterclockwise and back into the second (blocking) position when force is no longer applied to the left cam  82 . A return spring  83 , positioned within the elongate body  84 , acts between the elongate body and a pin  85  fixed within the channel  66  (see  FIG. 11 ) to force the left cam  82  away from the left outer cut-off  62  when force is no longer applied to the left cam. 
     As shown in  FIGS. 1 and 2 , shotgun  10  comprises a fore-end chassis  88  mounted on the receiver  12  and movable lengthwise along the right and left magazine tubes  26  and  58 . Shotgun  12  has a “pump action”, wherein motion of the fore-end chassis  88  away from the shotgun&#39;s muzzle end  90  (motion out of battery) opens the breech  20 , extracts and ejects the chambered round if any (spent or live), cocks the striking mechanisms, resets the fire control group  14  and releases the next round of ammunition from one of the magazines. Motion of the fore-end chassis  88  toward the muzzle end  90  (motion into battery) chambers the next round and closes the breech. 
     Coordination of ammunition feed from the right and left magazine tubes  26  and  58  to the chamber  18  is effected through a selector  92  mounted on the receiver  12  and shown in  FIGS. 2, 10 and 11 . In the example embodiment shown, selector  92  comprises a body  94  mounted on the fore-end chassis  88  and movable relatively thereto transversely to the right and left magazine tubes  26  and  58 . An activation surface  96  is mounted on the selector body  94  in facing relation with the right and left cams  52  and  82 . As shown by a comparison of  FIGS. 10 and 11 , transverse motion of the selector body  94  aligns the activation surface  96  with one of the right or left cams  52  and  82  such that lengthwise motion of the fore-end chassis  88  along the magazine tubes  26  and  58  toward the cams will bring the activation surface  96  into engagement with one of them.  FIG. 10  shows the activation surface  96  aligned so as to engage the right cam  52  and thereby release a round from the right magazine tube  26  as described below, and  FIG. 11  shows activation surface  96  aligned so as to engage the left cam  82 . To permit manual manipulation of the selector  92 , a right button  98  projects from one side of the selector body  94  transversely to the right and left magazine tubes  26  and  58 , and a left button  100  projects from an opposite side of the selector body transversely to the right and left magazine tubes. The right and left buttons  98  and  100  are adapted for manually moving of the selector body  94  transversely to the right and left magazine tubes  26  and  58  to align the activation surface  96  with one of the right or left cams  52  and  82 . In this example embodiment, pushing the left button  100  toward the right magazine tube  26  selects the right magazine tube as the tube from which the next round will be released ( FIG. 10 ). Likewise, pushing the right button  98  toward the left magazine tube  58  selects the left magazine tube as the tube from which the next round will be released ( FIG. 11 ). As shown in  FIG. 2 , it is advantageous that the right or left button project proud from the fore-end chassis  88  on the same side of the receiver  12  of the selected magazine. The buttons thus serve as visual and tactile indicators as to the magazine selected. Indicia may also be positioned on the buttons to provide a further visual indication as to the selected feeding magazine. As shown in  FIG. 11 , a spring and plunger detent  104  acting between the fore-end chassis  88  and the selector body  94  will help maintain the selector body securely in a desired position yet allow the selector body to be moved readily to select either magazine tube. 
     Shotguns for self-defense purposes having multiple magazines may suffer from a malfunction known as “lock up”, where a second shell is released from a magazine before a first shell has been chambered. This may occur, for example, when a first shell is released from one of the magazines and the selector is then switched and the user releases a second shell out of the other magazine by again drawing the fore-end chassis back out of battery before completion of a full return stroke chambering the previously released first shell. The first shell will not have completed its feeding cycle, and with the release of the second shell there will thus be two shells attempting to feed into the chamber as the fore-end chassis is subsequently moved to place the action in battery. The result will be the “locking up” of the action which remains out of battery without a shell chambered until the two shells are cleared from the firearm. 
     To avoid the lock up malfunction it is advantageous to use an interrupter mechanism  106 , shown in  FIGS. 10 and 12 , to prevent the manipulation of the selector  92  in all positions of the fore-end chassis  88  but the forward most end of travel placing the action in battery (see  FIG. 1 ). As shown in  FIG. 10 , an example interrupter  106  comprises an interrupter surface  108  mounted on the receiver  12 . In this example the interrupter surface  108  comprises a wall  110  mounted on the receiver  12  between the right and left magazine tubes  26  and  58 . In this particular embodiment the wall  110  extends lengthwise along the centerline of the shotgun  10 . The interrupter surface  108  (wall  110 ) has an end  112  positioned distal to the right and left outer cut-offs  32  and  62 . As shown in  FIG. 12 , interrupter  106  further comprises a boss  114  extending from the selector  92  toward the magazine tubes  26  and  58 . In this example, the boss  114  extends the selector body  94 . As shown in  FIG. 11 , the boss  114  is engageable with the interrupter surface  108  when the selector  92  is positioned between the wall&#39;s end  112  and the right and left outer cut-offs  32  and  62 , thereby preventing movement of the selector body  94  transversely to the right and left magazine tubes  26  and  58 . The wall&#39;s end  112  is positioned on receiver  12  such that it corresponds to a position of the fore-end chassis  88  which: 1) is substantially the full forward extent of travel of the fore-end chassis which places the action of shotgun  10  in battery; and 2) positions the selector  92  relatively to the wall&#39;s end  112  such that the boss  114  cannot engage the interrupter surface  108 , thereby allowing motion of the selector body  94  transversely to the magazine tubes  26  and  58  (see  FIG. 12 ). Thus the interrupter  106  permits selection of the right or left magazine only when the shotgun&#39;s action is in battery (the fore-end chassis  88  is fully forward) thereby preventing action lock up. 
     As shown in  FIGS. 4 and 5 , the shotgun according to the invention further comprises an inner cut-off  116  mounted on the receiver  12 . Similar to the outer cut-offs  32  and  62 , the inner cut-off  116  is mounted on the receiver via magazine tubes  26  and  58 . Inner cut-off  116  has first and second blocking surfaces  118  and  120  movable between a first position (see  FIG. 6 ) respectively blocking the right and the left bores  28  and  60  of the right and left magazine tubes  26  and  58 , and a second position (see  FIG. 5 ) not blocking the right and left bores. In the example embodiment shown, the blocking surfaces  118  and  120  are mounted on a lever  122 . Lever  122  is pivotably mounted on a housing  124  which in turn is mounted on the magazine tubes  26  and  58 . Lever  122  is pivotable about an axis  126  oriented transversely to the magazine tubes  26  and  58 . An inner biasing spring  128  acting between the housing  124  and the lever  122  biases the first and second blocking surfaces  118 ,  120  into the second (not blocking) position. An inner cam follower  130  is mounted on the lever  122 . An inner cut-off cam  132 , slidably mounted on the receiver  12  beneath the magazine tubes  26  and  58 , engages the inner cam follower  130  for pivoting the first and second blocking surfaces  118  and  120  between the first and second positions. As shown in  FIG. 9A  and in a comparison of  FIGS. 5 and 6 , the inner cut-off cam  132  comprises an angled nose  134  which is engageable with an inner action surface  136  comprising the inner cam follower  130  on lever  122 . Sliding motion of the inner cut-off cam  132  away from the muzzle end of shotgun  10  forces the angled nose  134  to engage the inner action surface  136  and pivot the lever  122  from the second (not blocking) to the first (blocking) position as described below and shown in  FIG. 6 . An inner cut-off cam actuator  138  movably mounted on the receiver  12  engages and moves the inner cut-off cam  132  into and out of engagement with the inner action surface  136 . In this example, the inner cut-off cam actuator  138  is mounted on the fore-end chassis  88  (see  FIG. 2 ). To move the lever  122  into the first (blocking) position shown in  FIG. 6 , the inner cut-off cam actuator  138  engages a tab  140   a  on the inner cut-off cam actuator  132  when the fore-end chassis  88  is moved away from the muzzle end of the shotgun to bring the action out of battery. Lever  122  is permitted to move back into the second (not blocking) position of  FIG. 5  under the force of inner biasing spring  128  as the fore-end chassis  88  is moved toward the muzzle end of shotgun  10 . As it moves toward the muzzle end of shotgun  10 , the inner cut-off cam actuator  138  engages a second tab  140   b  on the inner cut-off cam actuator  138  (see  FIGS. 9 and 9A ), drawing the nose  134  out of engagement with the inner action surface  136  as the shotgun&#39;s action is returned to battery. 
     Operation of the example ammunition feed system  24  according to the invention is described beginning with  FIGS. 1 and 2 , with the shotgun&#39;s action in battery as evidenced by the forward position of the fore-end chassis  88 . The user has selected the right magazine tube  26  from which to feed the next round into the chamber  18 . Magazine selection is accomplished by depressing the left selector button  100  (see  FIG. 10 ) to align the activation surface  96  of the selector  92  with the right cam  52 . Transverse motion of the selector body  94  relative to the receiver  12  is permitted because the fore-end chassis  88  is fully forward, positioning the interrupter boss  114  forward of the end  112  of interrupter surface  108  (see  FIG. 12 ). Right selector button  98  projects outwardly from the receiver  12  indicating right magazine selection. 
     In  FIG. 5 , the fore-end chassis  88  is drawn away from the muzzle end of shotgun  10  as indicated by the position of the inner cut-off cam actuator  138  which is mounted thereon.  FIG. 5  shows the inner cut-off cam actuator  138  as it first engages the tab  140   a  of the inner cut-off cam  132  (see also  FIGS. 4 and 9A ). As further shown in  FIG. 5 , the right lever  34  of the right outer cut-off  32  is positioned so that its right blocking surface  42  is in the first position blocking the right bore  28  of the right magazine tube  26  and thereby retaining shell  30  within the tube. The inner cut-off  116  is in its second position with both its first and second blocking surfaces  118  (shown) and  120  not blocking the bores  28  and  60  of the magazine tubes  26  and  58  (see also  FIG. 4 ). 
       FIG. 6  shows continued motion of the fore-end chassis  88  which moves the inner cut-off cam actuator  138  against the tab  140 , moving the inner cut-off cam  132  so that its angled nose  134  engages the inner action surface  136  of the inner cam follower  130 . This engagement causes the lever  122  of the inner cut-off  116  to pivot clockwise about axis  126  and position the first and second blocking surfaces  118  and  120  ( 118  shown) into the first position blocking the bores  28  and  60  of the magazine tubes  26  and  58 . Note that the first and second blocking surfaces  118  (shown) and  120  are offset toward the muzzle end of the shotgun from the right and left blocking surfaces  42  (shown) and  72  of the outer cut-offs  32  (shown) and  62  and thus will not prevent the shell  30  from being released from magazine tube  26 . The first and second blocking surfaces  118  and  120  will however, catch the next shell,  30 A, as described below. 
     As shown in  FIG. 7 , continued motion of the fore-end chassis  88  causes the activation surface  96  of selector  92  to engage the right cam  52 . Complementary ramp surface  56  of the right cam  52  engages the right ramp surface  50  of the right cam follower  44  on the right lever  34  of the right outer cut-off  32  (see also  FIG. 3 ). Right lever  34  pivots clockwise about axis  40  and moves the right blocking surface  42  into its second position not blocking bore  28  of the right magazine tube  26  and thereby releasing the shell  30  which is shown beginning to move out of the magazine tube. 
       FIG. 8  shows shell  30  being received by an elevator  142  which subsequently raises the shell to the breech  20  be chambered (see  FIG. 9 ). Meanwhile, the next shell  30 A advances toward the end of the magazine tube  26  but is blocked and retained within the magazine tube as it engages the first blocking surface  118  of the inner cut-off  116  which is held in the blocking position by the inner cut-off cam  132  under the action of the inner cut-off cam actuator  138  acting on tab  140   a.    
     As shown by the position of the inner cam actuator  138  in  FIG. 9 , the fore-end chassis  88  is moved toward the muzzle end of the shotgun. This motion of chassis  88  disengages the activation surface  96  of selector  92  (not shown) from the right cam  52 , thereby removing force from the right cam and allowing the cam&#39;s right return spring  53  (see  FIG. 3 ) to move the right cam out of engagement with the right lever  34 , thereby allowing the right biasing spring  46  to rotate the right lever  34  counterclockwise so as to position the right blocking surface  42  into its first position blocking the right magazine tube  26 . Contemporaneously, the inner cam actuator  138  also disengages from the first tab  140   a  of the inner cut-off cam  132  and subsequently engages the second tab  140   b  (see also  FIG. 9A ). Upon this subsequent engagement, further motion of the inner cam actuator  138  draws the nose  134  of the inner cut-off cam  132  out of engagement with the inner action surface  136  of lever  122 , allowing the lever to pivot counterclockwise under the force of inner biasing spring  128  and position the first and second blocking surfaces  118  (shown) and  120  back into the second (not blocking) position shown. Motion of the lever  122  is timed so that the first and second blocking surfaces  118  and  120  move into the second (not blocking) position only after the right blocking surface  42  of the right lever  34  has moved into its first (blocking) position. (The same timing conditions are also true for the left blocking surface  72  when ammunition feed is from the left magazine  58 .) Synchronization of the motion of right lever  34  with lever  122  and the chambering of shell  30  is ensured by controlling the relative and absolute positions of the first and second tabs  140   a  and  140   b  on the inner cut-off cam  132 . This condition is shown in  FIG. 9  where shell  30 A is retained within right magazine tube  26  by the right outer cut-off  32 . Shell  30  has meanwhile been chambered as the action moves fully into battery. Note also that the selector  92  (see  FIGS. 10-12 ) cannot be manipulated until the action is fully in battery and the boss  114  is clear of the interrupter surface  108  (wall  110 ) as shown in  FIG. 12 . This coordination of selector movement with selector position is expected to prevent locking up of the shotgun&#39;s action by preventing a second magazine from being selected before a shell has been chambered. Operation of the feeding system  24  when the left magazine tube  58  is selected is the same as when the right magazine tube is selected and is therefore not described in detail. 
     The design of the right and left outer cut-offs  32  and  62  and the inner cut-off  116  permits the left and right magazines  26  and  58  to be emptied without the need to cycle the action of shotgun  10 . This is especially convenient when many shells are present in the magazines and is also safer because no rounds being removed need to be first chambered during the process. With the shotgun  10  in battery as shown in  FIG. 1 , removal of shell  30  from the right magazine  26  is effected by depressing the right manual actuator surface  48  so as to pivot right lever  34  clockwise. This pivoting motion will move the right blocking surface  42  into its second (not blocking) position, and, because the first and second blocking surfaces  118  and  120  of the inner cut-off  116  remain in their second (not blocking) position, shell  30  will be forced out of the right magazine  26  by the action of the magazine spring (not shown). Upon release from the magazine tube  26  shell  30  falls out of the shotgun  10  through the open bottom between the pistol grip  144  and the butt stock  146 . If the right lever  34  is released then shell  30 A will be captured and retained within the right magazine tube  26  by the right outer cut-off  32  as the right blocking surface  42  pivots back into its first (blocking) position under the action of right biasing spring  46 . However, if the right lever  34  is continuously depressed then all of the shells within the right magazine tube  26  will be forced out. Removal of shells from the left magazine tube proceeds similarly. 
     Shotguns  10  according to the invention are expected to operate more reliably and with greater safety than those of the prior art.