Abstract:
The present invention provides for a stock kit that converts a conventional rifle, such as an SKS, into bullpup configuration. The preferred embodiment of the provided stock kit does not require any permanent modification be made to the host firearm. The stock kit also provides for a rotatable handguard, trigger safety and a magazine release.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention generally relates to firearms. More particularly, the present invention relates to stock kits which convert a traditional rifle into bullpup configuration. 
     2. Description of the Prior Art 
     Traditionally rifles using detachable magazines are configured so that the action of the firearm and the ammunition magazine are located in front of the trigger. Rifles configured so that the action and the magazine are located behind the trigger of the firearm are referred to as “Bullpups”. 
     Rifles in a bullpup configuration offer several advantages over the more traditional rifle configuration. One of these advantages relates to barrel length. A bullpup having the same overall length as a traditionally configured rifle will have a longer barrel. This is due to the positioning of the action closer to the rear end of the buttstock. Longer barrels are typically associated with increased accuracy and better external and terminal ballistic performance. 
     While the action and the mounting position of the ammunition magazine are moved towards the rear end relative to the buttstock, the position of the trigger stays relatively the same. This requires a new mechanism to place the trigger and the sear of the firearm&#39;s action into operational communication. 
     In certain instances, end users of more traditional rifles may desire to alter the appearance and functionally of their more traditionally configured rifle into that of a bullpup. This may be done to improve ergonomics, reduce weight, and reduce overall length without compromising ballistic performance. Such a modification would be particularly desirable if it required minimal expertise and mechanical skill. 
     In addition to a new rifle stock kit for the host firearm, a mechanism to reposition the trigger forward of the action and the magazine must be provided for in order to complete the bullpup conversion. 
     Therefore in consideration of what is available in the prior art, there exist a need for a rifle stock kit which converts a traditionally configured rifle into bullpup configuration. Such a stock kit should require minimal gunsmithing knowledge or mechanical expertise to install and provide a mechanism to reposition the trigger forward of the action and the magazine. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing, one object of the present invention is to meet the recognized need for such an apparatus that converts a traditionally configured rifle into bullpup configuration by providing a rifle stock kit which includes a mechanism for repositioning the trigger. 
     Another object of the present invention is to provide a rifle stock kit in accordance with the preceding objects which provides for a rotatable handguard that may be used as vertical foregrip. 
     Yet another object of the present invention is to provide a rifle stock kit in accordance with the preceding objects which provides a mechanism to facilitate removal of the ammunition magazine. 
     A further object of the present invention is to provide a rifle stock kit in accordance with the preceding objects which provides a trigger safety mechanism. 
     In accordance with these and other objects, the present invention is directed to a rifle stock kit which is configured to receive the barreled action of a firearm and convert it to a bullpup configuration. The rifle stock kit consists of a three piece chassis system, a mechanical device to connect the trigger provided by the stock kit to the sear of the barreled action, a mechanical trigger safety, a rotatable handguard and a magazine release. The preferred embodiment of the rifle stock kit is configured to work with a SKS type rifle. 
     The chassis system provided for herein consists of a body portion, top portion and a buttstock portion. The body portion is configured to receive the barreled action of an SKS type rifle. The body portion provides for a pistol grip and trigger that are located in front of the firearm&#39;s action and the firearm&#39;s magazine. Provided on the pistol grip is a mechanical safety which must be disengaged in order to operate the trigger. The trigger is provided with a mechanical link which extends therefrom back to the action of the SKS, placing the two into operational communication. 
     Located on the bottom portion of the chassis in front of the trigger is a handguard which is grasped by a users support hand during operation of the firearm. The handguard is rotatable and may be used as a foregrip, sometime referred to as a vertical foregrip. 
     Located adjacent to the magazine catch present on the action of the SKS is a magazine release lever. The magazine release lever is secured to the bottom portion of the chassis and provides two contact surfaces. By operating either contact surface the magazine may be quickly released. 
     These together with other improvements and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being made to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The novel features believed to be characteristic of the invention, together with further advantages thereof, will be better understood from the following description considered in connection with the accompanying drawings in which a preferred embodiment of the present invention is illustrated by way of example. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention. 
         FIG. 1  is a side perspective view of one side of a SKS type rifle&#39;s barreled action equipped with a bullpup stock kit in accordance with the present invention. 
         FIG. 2  is a side perspective view of another side of the SKS type rifle shown in  FIG. 1 . 
         FIG. 3  is an exploded perspective view of the bullpup stock kit assembly including the bottom, top and buttstock portions of the chassis assembly; the linking mechanism of the trigger and the barreled action of an SKS type rifle are also shown. 
         FIG. 4  is a side perspective view of the body portion of the bullpup stock kit&#39;s chassis in accordance with the present invention. 
         FIG. 5  is a top view of the body portion of the chassis shown in  FIG. 4 . 
         FIG. 6  is a top perspective view of the body portion of the chassis shown in  FIG. 4 . 
         FIG. 7  is an enlarged partial view of  FIG. 6  showing how the handguard cap adaptor is received within the body portion of the chassis. 
         FIG. 8  is a side perspective view of the handguard cap adaptor in accordance with the present invention. 
         FIG. 9  is a side view of the handguard cap adaptor shown in  FIG. 8 . 
         FIG. 10  shows a side perspective view of the chassis&#39;s top portion in accordance with the present invention. 
         FIG. 11  is a side view of the chassis buttstock portion in accordance with the present invention. 
         FIG. 12  is a side perspective view of the buttstock shown in  FIG. 11 . 
         FIG. 13  is an exploded side view of the body portion showing the rotatable handguard, trigger, trigger safety and magazine release in accordance with the present invention. 
         FIG. 14  is an exploded side view of another side of the body portion shown in  FIG. 13 . 
         FIG. 15  is a side view of the bullpup shown in  FIG. 1 . 
         FIG. 16  is a side cutaway view of the rifle shown in  FIG. 15 , in particular the first position of the trigger safety is shown. 
         FIG. 17  is a partial cutaway view of the rifle shown in  FIG. 15 , in particular the second position of the trigger safety is shown. 
         FIG. 18  is a side perspective view of the barreled action  11  used with the preferred embodiment of the invention shown in  FIG. 1 , also shown is the trigger and trigger link. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In describing a preferred embodiment of the invention illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose. 
     The present invention is directed towards a rifle stock kit that may be used to convert a traditionally configured rifle into bullpup configuration. The rifle stock kit also provides for an integrated rotatable handguard that may be used as a vertical foregrip, a trigger safety and a magazine release. As used herein, the phrases rifle stock kit and bullpup stock kit are used interchangeably. 
     It is to be understood that the term “action” as used throughout this specification includes the bolt, receiver and trigger mechanism of the firearm used with the preferred embodiment of the present invention. The firearm used with the preferred embodiment is a Samozaryadnyj Karabin sistemy Simonova rifle, commonly referred to as an SKS. The SKS is typically chambered to fire 7.62×39 mm ammunition. 
     Turning now to the drawings in which like reference characters indicate corresponding elements throughout the several views, as used herein, the word “front” or “forward” corresponds to where the muzzle end of the barrel is located (i.e., to the right as shown in  FIGS. 1 ,  3  and  15 - 17 ); “rear” or “rearward” or “back” corresponds to the direction opposite where the muzzle end of the barrel is located (i.e., to the left as shown in  FIGS. 1 ,  3  and  15 - 17 ). 
     As shown in  FIGS. 1-2  and  15 , the present invention is directed to a bullpup stock kit, generally designated by reference numeral  20 , for use with the barreled action  11  of an SKS type rifle. The combination of the barreled action  11  and the bullpup stock kit  20  is referred to as the bullpup configured rifle, or simply bullpup, and is designated by reference number  10 . 
     Best shown in the exploded view of  FIG. 3 , the bullpup stock kit  20  generally consists of a top portion  26 , a body portion  24 , a buttstock portion  28 , a trigger  30 , trigger safety  32 , a trigger link  34  and a magazine release lever  60 . The combination of the body portion  24 , top portion  26  and buttstock portion  28  are collectively referred to herein as the chassis  22 . Also shown in  FIG. 3  is a detailed view of an SKS rifles barreled action  11 . The barreled action  11  is comprised of an action  18  (receiver and bolt), barrel  14 , handguard cap  17  and gas tube  16 . The action  18  also has a trigger  13 , a sear  15 , a hammer  19 , and a magazine release  5 . The magazine release  5  is sometimes referred to herein as a magazine catch. 
     A perspective side view of the chassis&#39;s  22  body portion  24  is shown in  FIG. 4 . The chassis  22  is configured to receive the barreled action  11  in a channel  23  which extends between the back of the body portion  24  to its front. The channel  23  defines an interior bottom portion  40  with two side walls  41 A and  41 B extending therefrom. Side walls  41 A and  41 B generally occupy parallel plans. 
     Extending from the bottom side of the body portion  24  is a pistol grip  25  and a trigger guard  27 . The pistol grip  25  and trigger guard  27  are connected together. Located on the front end of the body portion  24  is a joint  29  to which the handguard  21  is mounted as shown in  FIGS. 1-3  and  15 - 17 . Located on the underside of the body portion  24  near the back end is an opening  61  configured to receive the magazine release  60  lever therein (see  FIGS. 1-3 ). Located adjacent to and connected with the opening  61  for the magazine release lever  60  is an opening  64  configured to receive a portion of the ammunition magazine  12  therein (see  FIG. 5 ). The opening  64  is often referred to as a magazine well. Located adjacent the rear most end of the body portion  24  is a thru-bore  42 . The function of which will be described in greater detail in the following paragraphs. 
     Located on each side wall  41 A and  41 B, above the trigger guard  27 , are two thru-bores  43 . The thru-bores  43  located on side wall  41 A are in alignment with the thru-bores  43  present on side wall  41 B. Located between the thru-bores  43  within the interior of the body portion  24  is a pocket  44  (see  FIGS. 4-7 ). The pocket  44  is configured to receive the handguard cap adaptor  70  described below (see  FIGS. 6-9 ). 
     The handguard cap adaptor  70  has a protruding lip  71  on its front end constructed to be received by a portion of the handguard cap  17  (see  FIGS. 16-17 ). It has an interior channel  72  configured to receive a portion of the barrel  14  therein when the barreled action  11  is secured within the body portion  24  of the chassis  22 . Four openings  73  through the top portion of the handguard cap adaptors&#39;  70  body are provided (see  FIGS. 7-9 ). There are two openings  73  on each side of the handguard cap adaptor  70 , each opening  73  being in alignment with an opening  73  located on the opposite side of the handguard cap adaptor  70 . When the handguard cap adaptor  70  is placed within the pocket  44 , the openings  73  are aligned with the thru-bores  42  of the body portion  24  of the chassis  22  (see  FIG. 7 ). Once the openings  73  are in alignment with the thru-bores  42 , two roll pins  45  (see  FIGS. 2-3 ) are used to secure the handguard cap adaptor  70  to the body portion  24  of the chassis  22 . Alternatively, a screw or friction pin may be used without departing from the scope of the present invention. 
     When the barreled action  11  is secured within the channel of the body portion  24 , a portion of the handguard cap  18  receives therein the protruding lip  71  of the handguard cap adaptor  70  (see  FIGS. 16-17 ). 
     The pocket  44  is constructed to receive handguard cap adaptors  70  of varying size (see  FIGS. 4-7 ). This is useful because the exact location of the handguard cap  17  on the gas tube  16  as it relates to the action  18  of the firearm varies based on the SKS rifles nation of origin. The overall length of the handguard cap adaptor  70  or the protruding lip  71  may be varied to accommodate the dimensional variations which exist between SKS type rifles manufactured at different arsenals. 
       FIG. 10  shows a side perspective view of the chassis  22  top portion  26 . The top portion  26  has an ejection port opening  80  which allows the user to operate the action  18  of the bullpup  10  and facilitates the ejection of spent ammunition cases during firing (see  FIGS. 1 ,  3 ,  10  and  15 ). Located on its forward most end is a protruding lip  81 . The protruding lip  81  has a generally “U” shape, similar to the protruding lip  71  of the handguard cap adaptor  70 . 
     The top portion  26  defines an interior opening  82  configured to fit around a portion of the barreled action  11 . Two side walls  83 A and  83 B are provided on the back end of the top portion  26 . Each side wall  83 A and  83 B defines an opening  84  therethrough which is in alignment with an opening  84  in the other side wall  83 A and  83 B. 
     The top side of the chassis&#39;s  22  top portion  26  includes an elevated mounting platform  85  ( FIG. 10 ). Secured to the elevated mounting platform  85  is a rail segment  89  (see  FIGS. 1-3  and  15 - 17 ). The rail segment  80  includes a number of rails extending therealong separated by traverse grooves  88  therebetween (see  FIGS. 3 and 15 ). In the illustrated embodiment, the rail segment  89  of the elevated mounting platform  85  is manufactured in accordance with the MIL-STD-1913 rail specifications. The rail segment  89  facilitates the attachment of iron sights and/or optical gun sights based on user preference. Other attachment surfaces which facilitate the attachment of optics and iron sights could be used in place of the rail segment  89  shown and described herein. In the preferred embodiment, the rail segment  89  is secured to the elevated mounting platform  85  through the use of screws. 
       FIGS. 11 and 12  show detailed illustrations of the chassis&#39;s  22  buttstock portion  28 . The back side  90  defines thereon a textured surface which prevents the bullpup  10  from slipping off of the users shoulder during firing. Extending from the back side  90  of the buttstock portion  28  are two arms  91 A and  91 B. Each of the arms  91 A and  92 B are configured to interface with the body portion  24  and top portion  26  of the chassis  22 . Near the proximal end of each arm  91 A and  91 B is an opening  92 A and  92 B, respectively. Also provided on the buttstock portion  28  is a thru-bore  94 , the purpose of which will be later described in detail. 
     The arms  91 A and  92 B are constructed to be received within an interior opening which is present after the body portion  24  and the top portion  26  of the chassis  22  are attached to the barreled action  11  during assembly. 
       FIGS. 13 and 14  show exploded views of the body portion&#39;s rotatable handguard  21 . The joint  29  has an opening  95  therethrough configured to receive a pin  93  (FIGS.  4  and  13 - 14 ). The opening  95  has an eight side star-shaped opening on one end which has tapered interior side walls and a generally circular opening on the other end. The pin  93  has a head  96  portion, a threaded portion  102  and a cylindrical body portion extending therebetween. The preferred embodiment pin  93  is a shoulder bolt. Also provided are a coil type spring  97 , a star-shaped locking piece  110  having a threaded interior opening and tapered exterior side walls and an end button  98  having a centrally located opening therethrough. 
     The rotatable handguard  21  is configured to be grasped by the user during use of the bullpup  10 . The preferred embodiment handguard  21  is also constructed so that it may be rotated and used as a vertical foregrip. Located on its forward end is an opening  99  which extends through sides walls  105 A and  105 B. The portion of opening  99  on side wall  105 B has the general shape of an eight point star, the interior side walls of which are tapered. The portion of opening  99  on side wall  105 A is generally circular (see  FIGS. 13 and 14 ). The handguard  21  defines an interior  100  area configured to be received against the body portion  24  when in the closed position (see  FIGS. 1-4 ). 
     To attach the handguard  21  to the body portion  24 , the gap  101  of the handguard  21  located generally between side walls  105 A and  105 B is placed about the joint  29  of the body portion  24 . When the joint  29  is within the gap  101 , opening  95  and opening  99  are in alignment with each other. The spring  97  and end button  98  are then placed within the circular portion of opening  99 . The star-shaped locking piece  110  is inserted into the star-shaped portions of opening  99  and  95 , respectively. The pin  93  is then inserted through the aligned openings  95  and  99  and threadedly secured to the star-shaped locking piece  110  (see  FIGS. 13 and 14 ). The end button  98  holds the spring  97  in place when the pin  93  is threadedly secured to the star-shaped locking piece  110 . 
     The star-shaped locking piece  110  secures the handguard  21  against unintentional movement when it is seated within opening  95  and  99 . The foregrip  21  may be disassembled by reversing the above outlined steps. 
     By varying the shape of the locking piece  110  and the appropriate portions of openings  95  and  99 , the number of positions into which the handguard  21  may be moved can be varied. The preferred embodiment of the handguard is provided with at least three positions of use. 
     The foregrip  21  may be placed in a closed position, also referred to as a first position, as shown in  FIGS. 1-4 . In its closed position, the rotatable handguard  21  acts as a conventional handguard. Alternatively, the handguard  21  may be rotated to a second or third position where is acts as a foregrip. The second position places the length of the handguard at an approximate 45 degree angle as it relates to the longitudinal axis of the body portion  24  of the chassis  22 . The third position places the handguard  21  into a vertical position where it is at an approximately 90 degree angle in relationship to the chassis&#39;s  22  body portion  24  (see  FIGS. 15-17 ). 
     The rotatable handguard  21  is moved between positions by pressing side wall  105 A towards the body portion  24 . This action compresses spring  97  and causes the star-shaped locking piece  110  of pin  93  to be pushed out of engagement with the star-shaped portion of opening  95 . The handguard  21  is the free to rotate to the next provided position at which time the pressure being placed on side wall  105 A is released. Once pressure is release from side wall  105 A the star-shaped locking piece  110  is received within another portion of the star-shaped portion of opening  95 . Once the star-shaped locking piece  110  has been received within the star-shaped portion of opening  95  the handguard is secured against unintentional movement. 
     The trigger  30  and trigger safety  32  provided by the bullpup stock kit  20  are mounted to the body portion  24  of the chassis  24  (see  FIGS. 1-3 ). The trigger  30  has two thru-bores  31 A and  31 B there through and defines a contact surface  46  thereon (see  FIGS. 13-14 ). The trigger safety  32  has one thru-bore  39  there through and defines a contact surface  47  thereon (see  FIGS. 13-14 ). The contact surfaces  46  and  47  of the trigger  30  and trigger safety  32 , respectively, are preferably textured. 
     The body portion  24  of the chassis  22  provides two openings  35  and  36  therethrough for mounting the trigger  30  and trigger safety  35 , respectively (see  FIGS. 1-5  and  13 - 14 ). Opening  36  also passes through the structure  37 , or mounting position, provided within the interior channel  23  of the body portion  24 . The provided structure  37  is constructed to receive the trigger  30  therein and minimize its side to side movement during operation (see  FIGS. 5 and 7 ). 
     The pistol grip  25  portion of the chassis  22  has a hollow  38  therein configured to receive the trigger safety  32 , trigger safety spring  33 , and a portion of the trigger  30  (see  FIGS. 4-5  and  16 - 17 ). The trigger safety  32  has a fist position of operation shown in  FIG. 16  and a second position of operation shown in  FIG. 17 . 
     The spring  33  biases the trigger safety  32  into the first position. The first position of the trigger safety  32  has the safety sear  48  engaged with a rearwardly protruding member  49  of the trigger  30 . This engagement between the safety sear  48  and protruding member  49  prevents the rearward movement of the trigger  30  (see  FIG. 16 ). 
     When the contact surface  47  of the trigger safety  32  is depressed towards the back side of the pistol grip  25 , the safety sear  48  is rotated out of engagement with the protruding member  49  of the trigger  30 . This is called the second position of the trigger safety  32  (see  FIG. 17 ). In this position, if the trigger  30  contact surface  47  is acted on by the user, the trigger  30  will move towards the rear allowing the bullpup  10  to be fired. 
     Another portion of the bullpup stock kit  20  is the magazine release lever  60  (see  FIGS. 1-3  and  15 - 17 ). The magazine release lever  60  has a thru-bore  50  located near its approximate center. Located on its forward face, near its top, is a textured contact surface  63 . Located adjacent its bottom surface is another contact surface  65 . Located opposite the contact surface  63  on the forward face of the magazine release lever  60  is the engagement surface  66  (see  FIGS. 16-17 ). 
     When the magazine release lever  60  is attached to the body portion  24  of the chassis  22 , the engagement surface  66  is in contact with the magazine release  5  of the action  18 . When the contact surface  63  of the magazine release lever is depressed, the engagement surface  66  pushes the magazine release  5  of the action  18  towards the rear of the rifle  10  allowing the magazine  12  to be removed. 
     Alternatively, the user may push the contact surface  65  provided on the bottom of the magazine release lever  60  forward. This motion causes the engagement surface  66  of the magazine release lever  60  to push the magazine release  5  of the action  18  towards the rear. The magazine  12  may be removed from the bullpup  12  once the magazine release  5  has been moved sufficiently towards the rear. 
     The magazine  12  is secured within the magazine well of the chassis  22 , to the barreled action  11  in a manner well known throughout the prior art as it concerns SKS type firearms. In alternate embodiments of the bullpup stock kit  20 , the method of securing a magazine into place will vary according to the barreled action used. 
     The magazine release lever  60  is secured to the body portion  24  of the chassis  22  as follows. The magazine release lever  60  is inserted into the opening  61  provided in the body portion  24 . The thru-bore  50  of the magazine release lever  60  is aligned with the opening  62  provided on the body portion  24  of the chassis  22 . When the thru-bore  50  is aligned with the opening  62 , a friction pin is inserted through the aligned openings thereby securing the magazine release lever  60  in place. The friction pin provides a surface about which the magazine release lever  60  rotates. 
       FIG. 18  shows a view of the barreled action  11  used with the preferred embodiment of the herein described invention. Also shown is the trigger  30 , trigger link  34  and the sear engagement member  52 . 
     When a barreled action  11  has been mounted in the chassis  22  of the present invention, a trigger link  34  extends between the trigger  30  provided for herein and the trigger  13  of the host firearms action  18  (see  FIG. 18 ). At its forward end, the trigger link  34  has a bend  51  which is received within a thru-bore  31 A of the trigger  30  (see  FIGS. 13-14  and  18 ). The trigger link  34  extends rearwardly from the trigger  30  towards the host firearms action  18 . The rearward end of the trigger link  34  is received within a thru-bore  54  located at one end of a sear engagement member  52 , or engagement member. When assembled therewith, the engagement member  52  extends perpendicular to the longitudinal axis of trigger link&#39;s  34  rearward end. The engagement member  52  has a generally cylindrical shape, the exterior surface of which has a plurality of flat surfaces  53  thereon (see  FIG. 18 ). 
     The engagement member  52  is secured to the trigger link  34  through the use of a set screw (not shown). A bore (not shown) is off set from the thru-bore  54  and threaded. This threaded bore receives a set screw which when tighten into place comes into direct contact with the trigger link  34 . While the set screw is in contact with the trigger link  34  the engagement member  52  is unable to move. This method of assembly allows for the precise placement of the engagement member  52  during installation. 
     The bullpup stock kit  20  is installed on a barreled action as follows. Initially the handguard cap adaptor  70  and the magazine release lever  60  are installed on the body portion  24  of the chassis  22  as described above. Then the spring  33  and trigger safety  32  are inserted within the hollow  38  of the pistol grip  25  (see  FIGS. 16-17 ). The thru-bore  39  of the trigger safety  32  is aligned with opening  36  of the body portion  24 . A friction pin is used to secure the trigger safety  32  and spring  33  into place within the hollow  38  of the body portion  24 . 
     The bend  51  of the trigger link  34  is now inserted into thru-bore  31 A of the trigger  30 . The trigger  30  is then inserted into the opening formed between the two walls which define its mounting position  37  within the body portion  24  of the chassis (see  FIG. 5 ). The trigger  30  is secured in place through the use of a roll pin which is inserted through opening  35  of the body portion and opening  31 B of the trigger  30  (see  FIGS. 1-2  and  15 ). 
     Next, the barreled action  11  is positioned above the body portion  24  of the chassis  22 . Then the sear engagement member  52  is installed on the trigger link  34  as described above (see  FIG. 18 ). The engagement member  60  is positioned on the trigger link  34  so that a portion of its exterior  53  is positioned behind the sear  15  of the action  18  when inserted therein. While the engagement member  60  is so positioned, the length of the trigger link  34  runs parallel to the longitudinal axis of the barreled action  11 . 
     The barreled action  11  is then inserted into the channel  23  of the body portion  22  so that the protruding lip  71  of the handguard cap adaptor  70  is received within the lower portion of the handguard cap  17  (see  FIGS. 16-17 ). Next, the top portion of the chassis  22  is placed over the top of the barreled action  11 . The top portion  26  is positioned so that the protruding lip  81  on its front end is received within a portion of the handguard cap  17  (see  FIGS. 1-2  and  15 - 17 ). The action  18  is received within the interior opening  82  of the top portion  26 . The arms  91 A and  91 B of the buttstock portion  28  are inserted into the opening formed between the top portion  26  and the body portion  24 . When properly installed, openings  92 A and  92 B of the buttstock portion  28  are in alignment with opening  84  of the top portion  26 . A pin is inserted through these aligned openings to secure the buttstock portion  28  to the top portion  26 . Concurrently, the thru-bore  94  of the buttstock portion  28  is also in alignment with the thru-bore  42  of the body portion  24 . A screw or friction pin is then inserted into the aligned thru-bores  42  and  94 , effectively securing the buttstock portion  28  to the body portion  24 . 
     To remove the bullpup stock kit  20  described above, simply reverse the above outlined steps. 
     When the trigger  30  is pulled to the rear the trigger link  34  is pulled forward. The forward movement of the trigger link  34  causes the engagement member  54  is push against the back side of the sear  15  of the action  18 . Once sufficient pressure has been applied to the sear  15 , the hammer  19  is released allowing the bullpup  10  to fire in a manner well know throughout the prior art. 
     Use of the magazine releaser lever  60  has been described in detail above. 
     The magazine release lever  60 , trigger  30 , trigger safety  32 , handguard  21  and the body portion  24 , buttstock portion  28  and top portion  26  of the chassis  22  are manufactured from nylon sixty six. While nylon sixty six is the preferred material, any material suitable for use with firearms may be substituted. All of these components are preferably manufactured through an injection molding process. 
     The exact shape and textures of the chassis&#39;s  22  exterior surfaces may be varied without departing from the scope of the invention disclosed herein. 
     In an alternate embodiment, the rotatable handguard  21  could be omitted entirely without departing from the scope of the present invention. In lieu of the rotatable handguard  21 , a non-moving handguard or a fixed position vertical foregrip could replace it. 
     In still another alternate embodiment, iron sights could be provided as part of the top portion  26  of the chassis  22  without departing from the scope of the present invention. 
     The foregoing descriptions and drawings should be considered as illustrative only of the general principles of the invention. This invention is not limited for use with the barreled actions of SKS types rifles; rather it may be used with any rifles barreled action which has a similar sear  15  mechanism. Numerous applications of the present invention will readily occur to those skilled in the art. Therefore, it is not desired to limit the invention to the specific examples disclosed or the exact construction and operation shown and described. Rather, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.