Patent Publication Number: US-9410764-B2

Title: Buttstock assembly

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present Patent Application is a divisional of U.S. patent application Ser. No. 13/573,156, filed Aug. 27, 2012, by the inventor named in the present Application. This Patent Application claims the benefit of the filing date of the United States Patent Application cited above according to the statutes and rules governing divisional patent applications, particularly 35 U.S.C. §§120 and 121 and 37 C.F.R. §1.78(d)(2) and (d)(3). The specification and drawings of the United States Patent Application referenced above are specifically incorporated herein by reference as if set forth in their entirety. 
    
    
     FIELD OF THE INVENTION 
     Embodiments of the disclosure are directed generally to firearms and, more particularly, to a modular, adjustable buttstock assembly for a firearm. 
     BACKGROUND INFORMATION 
     Most conventional firearms typically are adapted for specific tasks and generally are limited to use with specific calibers and/or types of ammunition. However, demand is increasing for firearms that can be modified to fire different types of ammunition, and/or can be reconfigured for different environments and uses. For example, in military applications today, the environments in which soldiers are forced to fight are changing such that they can be in open desert and then move into close quarters battle in a more urban area within the matter of a few hours. At the same time, their weapons needs can further change, i.e., they might be faced with need for a longer range, sniping weapon or alternatively with needs for a more standard infantry rifle depending on the environment or situation. Carrying multiple different firearms is, however, impractical as adding undue weight and bulk to soldiers&#39; packs and gear. Also, for more specialized uses, such as for sniping and other tactical situations, the weapon must be configurable as needed to fit the shooter&#39;s particular needs and/or use in a particular combat situation. 
     In addition, in operation of generally all types of firearms, the force of the expanding gas propelling a bullet/shot down the barrel upon firing also will force the firearm rearwardly in a recoil action. Accordingly, most rifles, shotguns, and similar types of firearms subject to a substantial recoil typically will include a buttstock for engaging the shooter&#39;s shoulder when firing the firearm to help support the firearm during a recoil action. It is becoming increasingly desirable that the buttstocks of such firearms accommodate different morphologies, comfort preferences, and other variables of different users, as well as supporting various equipment that may be used in conjunction with the firearm. It is also desirable, however, to minimize the overall weight of a firearm in military and civilian sporting applications. In addition, changes to features of the buttstock may be required in the field. For example, a user may want to adjust features of the buttstock to accommodate changes to the optics, caliber of ammunition, and/or barrel length of the firearm. It is desirable that such changes be able to be made in the field without requiring that a user carry additional tools, and that the changes can be made quickly and easily without compromising the performance of the buttstock during recoil. 
     Accordingly, it can be seen that a need exists for a buttstock apparatus for firearms that addresses the foregoing and other related and unrelated problems in the art. 
     SUMMARY OF THE DISCLOSURE 
     The present disclosure generally is related to a modular firearm comprising an adjustable, modular buttstock assembly. The buttstock assembly generally can be moveable between an extended position for placing the firearm in an operating configuration and a folded position for placing the firearm in a transport configuration. The buttstock assembly can include a frame with a central opening and at least one of a comb assembly with a cheek piece and a butt plate assembly having a recoil pad mounted to the frame by an adjustment apparatus. Each adjustment apparatus can include at least one of a guide post and a threaded adjustment post, each received in respective bores in the frame. The adjustment apparatus can include a feature that can selectively increase the friction between the frame and the guide post and adjustment post to help prevent the translation of the guide post and adjustment post in the bore in the frame. For example, a clamping mechanism, such as a toggle lock, a screw clamp apparatus, slide locking mechanism, or other releasable lock mechanism can be mounted to the frame at or proximate the bores in the frame receiving the guide post and adjustment post. In one example embodiment, the clamping mechanism can compress or clamp the bores into frictional engagement with the guide post and adjustment post, squeezing the guide post and adjustment post in the frame to secure the recoil pad and cheek piece in desired positions. 
     In one embodiment, the vertical position of the recoil pad further can be selectively adjusted. The butt plate assembly can include a base plate slidably coupled to a guide plate (e.g., with tongue and groove features). The guide plate, for example, can include an adjustment mechanism, such as a detent assembly that can selectively engage a notch of a series of notches in the base plate for selectively preventing or allowing vertical translation of the base plate relative to the guide plate. In one embodiment, the clamp mechanism is biased into engagement with the notch. 
     Features for attaching accessories to the buttstock assembly also can be mounted to the frame. For example, one or more accessory rails can be mounted to the frame via an adjustable bracket, or can be directly secured to a portion of the frame. Additionally, the frame can include features for attaching a sling swivel, or other similar features. 
     Those skilled in the art will appreciate the above features and advantages, as well as additional features and advantages upon reading the following detailed description with reference to the accompanying drawings and appendix. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A-1B  are isometric views of a firearm with a buttstock assembly according a first exemplary embodiment of the disclosure, the buttstock assembly shown in extended and folded positions. 
         FIGS. 2A and 2B  are isometric views of the buttstock assembly of  FIGS. 1A-1B . 
         FIG. 3  is an isometric, exploded view of a frame and accessory rail features of the buttstock assembly of  FIGS. 1A-1B . 
         FIG. 4  is a top view of the frame and adjustment features of the buttstock assembly of  FIGS. 1A-1B . 
         FIG. 5  is an isometric, exploded view of the frame and the adjustment features of  FIG. 4 . 
         FIG. 6A  is an isometric, exploded view of a butt plate assembly and a comb assembly of the buttstock assembly of  FIGS. 1A-1B . 
         FIGS. 6B and 6C  are isometric views of a base plate and a guide plate, respectively, of the butt plate assembly of  FIG. 6A  showing features for controlling vertical adjustment of the butt plate assembly. 
         FIG. 6D  is a top view of the butt plate assembly of  FIG. 6A . 
         FIGS. 7A and 7B  are isometric views of the frame and adjustment features of a buttstock assembly according to another exemplary embodiment of the disclosure. 
     
    
    
     Those skilled in the art will appreciate and understand that, according to common practice, the various features of the drawings discussed below are not necessarily drawn to scale, and that dimensions of various features and elements of the drawings may be expanded or reduced to more clearly illustrate the embodiments of the present invention described herein. 
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
     Referring now to the drawings in which like numerals indicate like parts throughout the several views, the figures illustrate example embodiments of the buttstock apparatus according to the principles of the present disclosure for use in a firearm such as a precision sniper rifle (PSR), modular sniper rifle (MSR), and/or similar types of firearms. However, it will be understood that the principles of the buttstock apparatus of the present disclosure can be used in various types of firearms including M4, M16, AR-15, SCAR, AK-47, HK416, ACR, shotguns, rifles and other long guns, hand guns, and other gas-operated semi-automatic, automatic and manually operable firearms. The illustrated embodiments, include by way of example, shows a bolt action firearm. However, the present disclosure should not be limited to the illustrated examples. 
     The following description is provided as an enabling teaching of exemplary embodiments, and those skilled in the relevant art will recognize that many changes can be made to the embodiments described. It also will be apparent that some of the desired benefits of the embodiments described can be obtained by selecting some of the features of the embodiments without utilizing other features. Accordingly, those skilled in the art will recognize that many modifications and adaptations to the embodiments described are possible and may even be desirable in certain circumstances, and are a part of the invention. Thus, the following description is provided as illustrative of the principles of the embodiments and not in limitation thereof. 
     As shown in  FIG. 1A , the firearm F generally includes a frame or chassis  10  including a receiver  12  and a barrel assembly  14  mounted to the receiver  12  at a front end  16  of the chassis  10  and defining a chamber at a position where the barrel assembly  14  connects to the receiver  12 . A bolt assembly  18  generally is slidably received in the receiver  12  for operation of the firearm F. A magazine well  20  is defined in the chassis  10  and in communication with the chamber, and an ammunition magazine  22  will be received in the magazine well  20  for supplying ammunition to the receiver  12 . A pistol-style handgrip  24  also can be connected to the chassis  10  adjacent a rear end  26  of the chassis  10 . A fire control  28  is mounted to the chassis  10  for controlling firing of the firearm F. A modular handguard assembly  30  further can be located along the front portion of the chassis  10  to assist in gripping and holding the firearm F. 
     In the illustrated embodiment, a buttstock assembly  50  is mounted to the rear end  26  of the chassis  10  at a hinge  52 .  FIG. 1A  shows the firearm F in a shooting configuration with the butt stock assembly  50  in an extended position, in line with the chassis  10 , with its hinge blocked or the buttstock assembly otherwise fixed against further pivoting movement.  FIG. 1B  shows the buttstock assembly in a folded position, pivoted forwardly toward the receiver. As illustrated in  FIGS. 2A and 2B , the buttstock assembly  50  includes a skeletonized body or frame  54 , and a hinge member  56  connected to a front end  58  of the frame  54  (e.g., by screws). The hinge member  56  is pivotally connected to hinge bracket  32  at the rear end  26  of the firearm chassis  10  by a hinge pin  60  ( FIGS. 1A-1B ). 
     As shown in  FIG. 3 , the frame  54  of the buttstock assembly has a reduced mass and/or surface area, defining a central open area or open space therein  62 . The shape of the frame  54  can provide a suitable structure for transferring the force of the recoil to the butt plate assembly (described below) without compromising the integrity of the buttstock assembly  50 . In addition, the central open space  62  helps to reduce the mass and weight of the buttstock assembly  50 , which helps reduce the overall weight of the firearm F. The frame  54  can be made of a light-weight, high strength material (e.g., aluminum, magnesium, steel, other metals and metal alloys, polymers, carbon fiber, etc.), or any other suitable material. The frame  54  also can include one or more sling bores  66 , which can be formed at different locations along the frame, for example at the front end  58  and a rear end  68 , respectively, of the frame as shown in  FIGS. 2A-3 , for attaching a sling swivel (not shown) or other features for securing a sling (not shown), for example, to the firearm F ( FIGS. 1A-1B ). In one embodiment, the frame  54  can be formed as an at least partially solid section or unitary piece of material extending around the central opening  62 . Alternatively, at least a portion of the frame  54  can comprise a hollow tube extending at least partially around the central opening  62 , with a channel such as for routing of wires, etc. . . . , formed therethrough. The frame  54  further can be otherwise configured or portions thereof omitted without departing from the scope of the disclosure. 
     As shown in  FIGS. 2A, 2B, and 3 , a bottom accessory rail  70  (e.g., Picatinny rail) can be secured to the bottom of the frame  54 , such as by screws  72  or other fasteners so that the bottom accessory rail  70  can be removed or replaced. Additionally, a side accessory rail  74  (e.g., Picatinny rail) can be secured to the frame  54  via a bracket  76 . In the illustrated embodiment, the bracket  76  is generally T-shaped with a longitudinal portion  78  (e.g., generally parallel to the barrel) and a vertical portion  80 . The side accessory rail  74  can be secured to the longitudinal portion  78 , such as by screws  82  or other fasteners so that the side accessory rail  74  can be removed or replaced. 
     As shown in  FIG. 3 , the frame  54  can include two or more protuberances  84  extending into central opening  62  of the frame, with the vertical portion  80  of the bracket  76  being secured to the protuberances  84 , such as by fasteners  86 . In one embodiment, the vertical faces of the protuberances  84  can be inset or spaced apart from the sides of the frame  54  so that the thickness of the bracket  76  is at least partially disposed in the central opening  62  of the frame. The protuberances  84  and the bracket  76  also can be generally symmetric so that the bracket  76  can be mountable in varying orientations and/or on either side of the frame  54 . Accordingly, the side accessory rail  74  can be ambidextrously positioned for use by either a right- or left-handed shooter. 
     In an alternative embodiment, the bottom accessory rail  70  and/or the bracket  76  could be riveted or adhered to the frame  54  or integrally formed with the frame, and the side accessory rail  74  could be riveted or adhered to or integrally formed with the bracket  76 . In another alternative embodiment, an accessory rail or other attachment feature can be secured to any surface of the frame  54 , and could be provided with a variety of configurations or omitted, without departing from the disclosure. 
     In the illustrated embodiment, as shown in  FIGS. 1A-1B , the buttstock assembly  50  can include a comb assembly  88  and a butt plate/recoil pad assembly  90 , each coupled to the frame  54  by a respective adjustment apparatus  92   a ,  92   b  ( FIGS. 2A and 2B ). As shown in  FIGS. 4 and 5 , each of the adjustment apparatus  92   a ,  92   b  generally includes a lock mechanism  93 , which can include clamping mechanism such as a toggle lock, slide lock, screw clamp, set screw, or other, similar lock/clamping mechanism. In the illustrated embodiment, a throw lever assembly  94  is shown attached to the frame in a position oriented transverse to a slit or separation channel  96  cut through the frame. A guide post  98  and a threaded adjustment post  100  ( FIG. 6A ) further are received in respective through-bores  102 ,  104  in the frame for each adjustment apparatus  92   a ,  92   b . The bores  102 ,  104  are coextensive with the slits or separation channels  96 , and one of the bores  102 / 104 , i.e., bore  104  can be internally threaded for engagement with the external threads of the adjustment post  100 . An adjustment wheel  106  can be attached to each of the adjustment posts  100  so that a user can grip the adjustment wheel  106  to screw the adjustment post into and out of the central opening  62  of the frame  54 . Relief cuts  108 ,  110  ( FIG. 5 ) can be formed on respective sides of the frame  54 , centered on each of the slits  96 . Accordingly, a deflection portion  112  of the frame is defined between each slit  96  and respective relief cut  108 , and a deflection portion  114  of the frame is defined between each slit  96  and respective relief cut  110  so that the deflection portions  112 ,  114  are spaced apart from one another by the portion of the slit  96  between the bores  102 ,  104 . 
     In the illustrated embodiment, the deflection portions  112 ,  114  can be squeezed or clamped toward one another, pivoting at the ends of the slit  96 , to reduce the width of the slit  96  and thereby reduce the diameters of one or both of the bores  102 ,  104 . Accordingly, the frame  54  is tightened around the guide post  98  and/or the adjustment post  100  at the bores  102 ,  104  to help prevent translation of the guide post and/or the adjustment post relative to the frame. Relieving the clamping of the deflection portions  112 ,  114  will allow the guide post and/or adjustment post to translate relative to the frame so that the positioning of the comb assembly  88  and the butt plate assembly  90  can be adjusted. 
     In the illustrated embodiment, the throw lever assemblies  94  generally form toggle clamps mounted to or adjacent the deflection portions  112 ,  114 , typically being oriented transverse to the slits  96 . As shown in  FIGS. 4 and 5 , each of the throw lever assemblies  94  includes a lever lock plate  116  disposed in the respective relief cut  108  and a locking nut plate  118  disposed in the respective relief cut  110 . Each of the lever lock plate  116  and the locking nut plate  118  includes a through bore that is aligned with through bores formed in the deflection portions  112 ,  114  of the frame  54  to form a through bore  120  that receives a cross pin  122  of the respective throw lever assembly  94 . A nut  124  or other fastener can be at least partially received in the locking nut plate  118  to threadedly engage the cross pin  122  and thereby secure the cross pin to the frame  54  with the lever lock plate  116  and locking nut plate  118  secured between the head  126  of the cross pin  122  and the nut  124 . 
     A thumb tab or lever  128  is pivotably coupled to the head  126  of the cross pin  122  by a pivot pin  130 , and a lever lock  132  is pivotably coupled to the thumb tab  128  by a pivot pin  134 . The thumb tab  128  includes cam lobes  136  disposed on either side of the head  126  of the cross pin  122 , and an off-center bore  138  extends through each of the cam lobes  136 . The bore  138  is aligned with a bore  140  in the head  126  so that the pivot pin  130  can extend through the bores  138 ,  140 . Accordingly, the thumb tab  128  can pivot relative to the cross pin  122  about the pivot pin  130 . The cam lobes  136  include cam surfaces  142 , which can engage corresponding indentations or surfaces  144  in the lever lock plate  116  so that the cam surfaces  142  can slide or pivot over the surface of the lever lock plate  116 . The cam lobes  136  also generally are configured so that when the thumb tab  128  is in the release position (e.g., when the thumb tab is pivoted away from the frame  54 ), the pivot pin  130  is closer to the lever lock plate  116  than when the thumb tab  128  is in the lock position (e.g., when the thumb tab is disposed against the frame  54 ). Stated another way, the distance D 1  ( FIG. 4 ) between the pivot pin  130  and the portion of the cam surfaces  142  in contact with the lever lock plate  116  when the thumb tab  128  is in its locking position is larger than the distance D 2  ( FIG. 4 ) between the pivot pin  130  and the portion of the cam surfaces  142  in contact with the lever lock plate  116  when the thumb tab  128  is in its opened or release position. Accordingly, when the thumb tab  128  is in its locking position (e.g.,  FIG. 4 ), the cam lobes  136  push or bear against the indentations  144  of the lever lock plate  116  and move the cross pin  122  via the pivot pin  130  against the nut  124 . The cam lobes  136  and the nut  124  accordingly bear against the respective lever lock plate  116  and locking nut plate  118 , urging the deflection portions  112 ,  114  toward one another, at least partially closing the slit  96 . As a result, the frame  54  is placed into frictional engagement with the adjustment apparatus of the comb assembly and/or butt plate assembly including the actuated throw lever assembly, as the bores  102 ,  104  are closed/tightened around the respective guide post  98  and/or the adjustment post  100  to clamp the guide post and adjustment post in place. 
     As shown in  FIG. 5 , the lever lock  132  includes a lock end  146  and an actuating end  148 . The lock end  146  can be biased downwardly to engage a notch  150  in the head  126  of the cross pin  122  by a spring (not shown) engaging the pivot pin  134  and the lever lock  132 . The lever lock  132  can be aligned so that pulling up on the thumb tab  128  will urge the lock end  146  against the notch  150 , and the lever lock  132  will resist pivoting of the thumb tab. Pushing downwardly on the actuating end  148  will pivot the lock end  146  upwardly against the spring bias and out of the notch  150 , and the thumb tab  128  can be pivoted upwardly. After the thumb tab  128  pivots a short distance, its actuating end  148  can be released, and the lever lock  132  will be pivoted so that the lock end  146  contacts the curved outer surface of the head  126  of the cross pin  122 . The lock end  146  further will slide along the outer surface of the head  126  as the thumb tab  128  continues to pivot to the release position. As the thumb tab  128  is moved into the lock position, the lock end  146  will engage the notch  150  to lock the thumb tab in position. The thumb tab  128  and the lever lock  132  can be otherwise configured or omitted without departing from the disclosure. 
     In the illustrated embodiment, the relief cuts  108 ,  110  are generally substantially identical in size and/or configuration, enabling the throw lever assemblies  94  to be easily reconfigured for ambidextrous use by either right- or left-handed users. Accordingly, while the throw lever assemblies  94  are assembled with the thumb tabs or levers  128  on the right side of the firearm F in  FIGS. 1A, 2A, 2B, 4, and 5 , the lever lock plate  116  and the locking nut plate  118  can be switched so that the lever lock plate  116  is on the left side of the firearm and the locking nut plate  118  is on the right side of the firearm. The thumb tabs  128  thus can be disposed on the left side of the firearm, engaged with the lever lock plate  116 , and the cross pin  122  can be inserted into the through bore  120  from the left side of the firearm to engage the nut  124  on the right side of the firearm. The throw lever assemblies  94  can be otherwise configured or omitted without departing from the disclosure. 
     It will also be understood by those skilled in the art that the adjustment apparatus  92   a ,  92   b  can be otherwise configured and/or features thereof can be modified or omitted without departing from the disclosure. For example, the guide post  98  or the adjustment post  100  could be omitted for one or both of the adjustment apparatus  92   a ,  92   b . While the comb assembly  88  or the butt plate assembly  90  could be supported by the respective guide post  98  alone when the guide posts  98  are clamped to the frame  54  by the throw lever assemblies  94 , the adjustment posts  100  can provide additional support to the clamping of the throw lever assemblies  94  by the threaded engagement of the adjustment posts  100  with the frame  54  at the bores  104  whether the guide posts  98  are included or omitted. 
     In an alternative embodiment, the adjustment features  92   a ,  92   b  can include any suitable apparatus that squeezes or clamps the guide post  98  and/or the adjustment post  100  in the frame  54  or otherwise increases or protrudes a frictional engagement between the frame  54  and the guide post  98  and/or the adjustment post  100  to help prevent the guide post  98  and/or the adjustment post  100  from moving relative the frame  54 . For example, a slide lock or twist lock clamping mechanism could be used in place of the throw lever assemblies  94  ( FIGS. 1A-5 ) or the screw clamp assemblies  94 ′ ( FIGS. 7A and 7B ). 
     As shown in  FIG. 6A , the comb assembly  88  includes a cheek piece  152  and a comb mounting bracket  154 . A user can rest his or her cheek against the cheek piece  152  when using optics (not shown) or other features associated with the firearm F. The cheek piece  152  can be made of a polymer, synthetics, rubber, or other materials that are comfortable for the user (e.g., a resilient cushioning material). In one embodiment, brass or other material inserts can be press fitted or otherwise secured into openings  156  in the bottom of the cheek piece  152 , and screws  158  can secure the comb mounting bracket  154  to the cheek piece  152  via these inserts. The cheek piece  152  can be adjusted forwardly and rearwardly by aligning the screws  158  with respective openings  156  associated with the desired position of the cheek piece. The comb mounting bracket  154  can be secured to the guide post  98  and the adjustment post  100  of the adjustment apparatus  94   a  with screws  160  so that moving the adjustment post  100  inwardly and outwardly with respect to the frame  54  (when the thumb tab  128  is in the release position) will move the comb assembly  88  downwardly and upwardly, respectively. A hex key  162  also can be stored in a longitudinal bore (not shown) in the cheek piece  152 , as needed, for loosening and tightening the screws  158 ,  160 , or other screws in the buttstock assembly  50 . The comb assembly  88  can be otherwise configured or omitted without departing from the disclosure. 
     As shown in  FIGS. 6A-6C , the butt plate assembly  90  includes a recoil pad  164  secured to a base plate  166  by screws  168  and a guide plate  170  secured to the guide post  98  and the adjustment post  100  of the adjustment apparatus  94   b  with screws  172 . The recoil pad  164  can be made of polymer, rubber, synthetics or other materials that are comfortable for the user (e.g., a resilient cushioning material) when engaging the buttstock assembly  50  against the user&#39;s shoulder, and different size or thickness recoil pads can be easily substituted or used as needed. In addition, the recoil pad  164  is adjustably positionable in multiple directions, including in both a longitudinal or first direction and a second direction, typically vertically or otherwise transversely to the first direction as discussed below. 
     The base plate  166  includes a tongue feature  174  on a forward surface of the base plate, and the guide plate  170  includes a groove feature  176  on a rearward surface of the guide plate. The tongue  174  includes sloped edges  178  along the height of the base plate on either side of the tongue. Similarly, the groove  176  has sloped edges  180  along the height of the guide plate. Accordingly, the tongue  174  can be received in the groove  176  with the sloped edges  178  interfacing with the sloped edges  180  ( FIG. 6D ) so the tongue, and the base plate  166 , can translate vertically with respect to the guide plate  170 , but the tongue  174  generally will be prevented from being easily pulled out of the groove  176  in the longitudinal direction. The base plate  166  can further include an adjustment limit pin  182  integrally formed therewith or securely received (e.g., press fit) in a longitudinal bore in the base plate. The adjustment limit pin  182  can be received in an adjustment limit groove  184  in the guide plate  170  so that the adjustment limit pin  182  can slide within the adjustment limit groove  184 . Accordingly, the adjustment limit pin  182  will limit the vertical translation of the recoil pad  164  and the base plate  166  relative the guide plate  170  by the length of the adjustment limit groove  184 . 
     As shown in  FIGS. 6B and 6C , the vertical translation of the recoil pad  164  and the base plate  166  further can be controlled by a pad adjustment assembly  186  provided along the guide plate  170  and which can comprise a detent mechanism  187  ( FIG. 66 ) that engages a series of notches  188  in the tongue  174  of the base plate  166 . The pad adjustment assembly  186  includes a clamp plate  190 , an adjustment button  192 , a clamp pin  194  or similar engaging member adapted to fit within one of the notches  188 , and a biasing spring  196 . The clamp plate  190  is disposed in a cut out portion  198  in the rearward surface of the guide plate  170  so that the clamp plate  190  can translate in a transverse direction, and the biasing spring  196  biases the clamp plate  190  so that a portion of the clamp plate extends into the groove  176 . The clamp pin  194  projects from the clamp plate and is biased into an engaging position projecting into the groove  176  for engaging a respective notch  188  ( FIGS. 6A-6B ) in the tongue  174 . The adjustment button  192  ( FIG. 6C ) extends from a side of the guide plate  170  and is in communication with the clamp plate  190  via a transversely extending bore  200  formed in the guide plate. Accordingly, the base plate  166  normally is biased to be coupled to the guide plate  170  by the engagement of the clamp pin  194  with one of the notches  188 . 
     In the illustrated embodiment, the adjustment button  192  can be depressed to push the clamp plate  190  against the biasing spring  196  to move the clamp pin  194  toward a non-engaging position out of the groove  176 . The clamp pin  194  thereby is disengaged from the notch  188 . The tongue  174  then can translate up or down in the groove  176  to reposition the base plate  166  and the recoil pad  164  relative to the guide plate  170  and the frame  54 . With the recoil pad  164  in a desired position, the adjustment button  192  can be released so that the biasing spring  196  urges/moves against the clamp plate  190  so as to move the clamp pin  194  back into the groove  176 , toward an engaging position for engaging and being received within one of the notches  188  of the tongue  174  of base plate  166 . The movement of the clamp plate  190  will move the adjustment pin  192  in the transverse bore  200  back into the original position. In one embodiment, the clamp pin  194  can fit securely in each of the notches  188  so that the clamp assembly  186  and the notches  188  can provide smooth and easy locking and unlocking of the base plate  166  and the guide plate  170  while limiting or eliminating vertical movement of the base plate  166  relative to the guide plate  170  (e.g., slack) when the clamp assembly  186  is engaged with one of the notches  188 . 
     In one embodiment, spacer plates (not shown) also can be added to the butt plate assembly  90  to move the recoil pad  164  further rearwardly in addition to the translation of the guide post  98  and adjustment post  100  of the adjustment apparatus  92   b . The butt plate assembly  90  can be otherwise configured or omitted without departing from the disclosure. 
     In operation, the vertical position of the comb assembly  88  and/or the longitudinal spacing of the butt plate assembly  90  can be adjusted by releasing the throw lever assemblies  94  so that the guide post  98  and the adjustment post  100  can translate relative to the frame  54 . Particularly, the actuating end  148  of the lever lock  132  can be depressed to disengage the lock end  146  of the lever lock from the notch  150  in the head  126  of the cross pin  122 . The thumb tab or lever thereof  128  then can be pivoted upwardly about the pivot pin  130  and the head  126 . The cam lobes  136  rotate as the thumb tab  128  is pivoted, and the cam surfaces  142  slide along the indentations  144  in the lever lock plate  116 . Accordingly, the distance between the pivot pin  130  and the portions of the cams surfaces  142  in contact with the lever lock plate  116  decreases as the thumb tab  128  is pivoted to the release position. In one embodiment, the pivot pin  130  is spaced apart from the lever lock plate  116  by the distance D 1  ( FIG. 4 ) when the thumb tab  128  is in the release position. With the thumb tab  128  in the release position, the clamping force on the deflection portions  112 ,  114  of the frame  54  is reduced or eliminated, reducing the friction between the frame and the guide post  98  and the adjustment post  100  at the respective bores  102 ,  104 . Accordingly, the adjustment wheel  106  can be turned to move the adjustment post  100  inwardly or outwardly of the frame, moving the comb assembly  88  or the butt plate assembly  90 . 
     Once the comb assembly  88  and/or the butt plate assembly  90  has been adjusted to a desired position, the respective throw lever assembly  94  of the adjustment apparatus  92   a  or  92   b  thereof can be moved to the lock position to secure the guide post and the adjustment post. Particularly, the thumb tab  128  can be pivoted to the lock position ( FIGS. 2A and 4 ), pivoting the cam lobes  136  so that the pivot pin  130  is spaced apart from the lever lock plate  116  by the distance D 1  ( FIG. 4 ). The lock end  146  of the lever lock  132  can engage the notch  150  in the head  126  of the cross pin  122  when the thumb tab  128  is in the lock position to help retain the thumb tab in the lock position. In the lock position, the cam lobes  136  bear downwardly on the lever lock plate  116  and the cross pin  122  pulls upwardly on the nut  124 , which bears on the locking nut plate  118 . The deflection portions  112 ,  114  are squeezed between the lever lock plate and the locking nut plate, narrowing the slit  96  and closing/tightening the frame  54  around the guide post  98  and the adjustment post  100 . Accordingly, the throw lever assemblies  94  help lock the guide post  98  and the adjustment post  100  in position. 
     In the illustrated embodiment, a latch mechanism  202  for the foldable buttstock assembly  50 , can be provided, being operable to selectively enable pivoting of the buttstock assembly  50  between an extended configuration ( FIG. 1A ) and a folded configuration ( FIG. 1B ). In the extended position shown in  FIG. 1A , the buttstock assembly  50  extends rearwardly from the rear end  26  of the chassis  10 , in line with the chassis  10 , enabling the firearm to be operated. In the folded configuration, the buttstock assembly  50  extends forwardly from the rear end  26  of the chassis  10 , substantially parallel to the chassis  10 , and is secured to a lateral side of the chassis  10 , thereby reducing the length of the firearm F to facilitate transporting the firearm. The latch mechanism can comprise a variety of stock latching systems for securing the buttstock assembly in its extended and folded configuration as needed. For example, a latch mechanism as disclosed in U.S. patent application Ser. No. 12/640,531, the disclosure of which is incorporated as if fully set forth herein, can be used. 
       FIGS. 7A and 7B  are isometric views of the frame  54  with clamping mechanisms for tightening the frame  54  about the guide post  98  and/or the adjustment post  100  according to a second embodiment of the disclosure. The second embodiment is generally similar to the first embodiment, except for variations noted and variations that will be apparent to one of ordinary skill in the art. Accordingly, similar or identical features of the embodiments have been given like or similar reference numbers. As shown in  FIGS. 7A and 7B , each of the adjustment apparatus  92   a ′,  92   b ′ includes a screw clamp assembly  94 ′. Each screw clamp assembly  94 ′ includes a pair of clamp plates, including a first or screw lock plate  116 ′ disposed in the relief cut  108  and a second or screw nut plate  118 ′ in the relief cut  110 . Each of the screw lock plate  116 ′ and the screw nut plate  118 ′ includes a bore that is aligned with the through bore  120  of the deflection portions  112 ,  114  of the frame  54 . The bore in the screw nut plate  118 ′ can be threaded to engage an adjustable fastener such as a cross screw  122 ′, which can be inserted into the bore  120  from the right side of the firearm F. 
     In an alternative embodiment, the bore in the screw nut plate  118 ′ can be a clearance fit with the cross screw  122 ′, and a nut (not shown) can engage the cross screw at the bore in the screw nut plate. The screw clamp assemblies  94 ′ can be easily switched so that the screw lock plate  116 ′ is disposed in the relief cut  110  on the left side of the firearm, the screw nut plate  118 ′ is disposed in the relief cut  108  on the right side of the firearm, and the cross screw  122 ′ is inserted into the bore  120  from the left side of the firearm. The cross screws  122 ′ can be configured to be tightened and loosened by a screwdriver, a hex key (e.g., hex key  162 ), or other tool. The screw clamp assemblies  94 ′ could be otherwise shaped, arranged, and/or configured without departing from the disclosure. 
     In operation, the vertical position of the comb assembly  88  and/or the longitudinal spacing of the butt plate assembly  90  can be adjusted by loosening the respective cross screw  122 ′ so that the guide post  98  and the adjustment post  100  can translate relative to the frame  54 . The adjustment wheel  106  can be turned to move the adjustment post  100  inwardly or outwardly of the frame, moving the comb assembly  88  or the butt plate assembly  90  accordingly. With the comb assembly  88  and/or the butt plate assembly  90  in a desired position, the respective cross screw can be tightened (e.g., with a hex key). The tightening of the cross screw  122 ′ causes the head of the screw to bear against the screw lock plate  116 ′ as the end portion of the cross screw that is threadedly engaged with the screw nut plate  118 ′ urges the screw nut plate  118 ′ toward the screw lock plate  116 ′. As these clamp plates are drawn together, the deflection portions  112 ,  114  are urged toward one another between the screw lock plate and the screw nut plate, narrowing the slit  96  and closing/tightening the frame  54  around the guide post  98  and the adjustment post  100 . Accordingly, the screw clamp assemblies  94 ′ help lock the guide post  98  and the adjustment post  100  in position until the cross screws  122 ′ are loosened. 
     It therefore can be seen that the construction of the firearm with an adjustable modular buttstock assembly according to the principles of the present disclosure provides a firearm with a lightweight yet highly configurable buttstock assembly while further providing for substantially quick and easy adjustment and reconfiguration of features of the buttstock assembly. 
     Those skilled in the art will appreciate that many modifications to the exemplary embodiments are possible without departing from the scope of the invention. In addition, it is possible to use some of the features of the embodiments described without the corresponding use of the other features. Accordingly, the foregoing description of the exemplary embodiments is provided for the purpose of illustrating the principle of the invention, and not in limitation thereof, since the scope of the invention is defined solely be the appended claims.