Patent Publication Number: US-7717024-B2

Title: Over riding chamber impulse average weapon

Description:
This application is a Divisional of application Ser. No. 11/531,410, filed Sep. 13, 2006 now U.S. Pat. No. 7,526,991, which claims priority to U.S. Provisional Application No. 60/722,014, filed Sep. 30, 2005, both of which being incorporated by reference in their entirety. 

   FIELD OF THE INVENTION 
   Embodiments of the invention relate to an automatic weapon. More specifically, embodiments of the invention relate to a recoil operated automatic weapon and a linkless ammunition feed system. 
   BACKGROUND OF THE INVENTION 
   Throughout history, military forces have been employed in offensive, defensive, and peace-keeping roles. Recent events have presented a need to perform these roles in tight quarters situations set in urban environments. Accordingly, a need exists for a lightweight weapon. 
   Lightweight automatic firearms have been produced to meet these needs. However, many lightweight firearms are subject to reduced accuracy resulting from the repeated recoil forces to which the user is submitted when firing in an automatic mode. Therefore, a need exists for a lightweight firearm, that does not sacrifice the accuracy of heavier weapon systems. 
   SUMMARY OF THE INVENTION 
   An embodiment of the present invention provides a firearm for firing cylindrically-shaped cased telescoped or case-less ammunition. The firearm comprises a barrel having a longitudinal bore axis, and a bolt that is collinear with the barrel&#39;s bore axis and adapted for linear movement between a charged position and a firing position. The movement of the bolt is relative to the barrel and parallel to the barrel&#39;s bore axis. The firearm further comprises a chamber that has a cylindrically-shaped ammunition-holding cavity formed within. The ammunition-holding cavity has a diameter sized to receive a cylindrically-shaped round of ammunition, the ammunition-holding cavity is also collinear with the barrel&#39;s bore axis. The chamber is also adapted for linear movement between a charged position and a firing position, with linear chamber movement being relative to the barrel and collinear with the barrel&#39;s bore axis. In the charged position, the chamber is positioned rearward of and away from the barrel, the bolt is also in its charged position and a forward surface of the bolt is generally coplanar with a forward surface of the chamber, with the bolt occupying the ammunition-holding cavity. In the firing position, a forward surface of the chamber sealingly contacts a rearward surface of the barrel, the bolt is also in its firing position and a forward end of the bolt sealingly contacts a rearward end of the chamber, with the chamber ammunition-holding cavity largely vacated by the bolt. 
   A further embodiment of the present invention further provides a method of charging a firearm. The firearm of the method comprises a barrel with a longitudinal bore axis, and a generally cylindrically-shaped firing pin having a lug extending from a circumferential surface, a bolt comprising a generally cylindrically-shaped internal cavity, a slot extending from the internal cavity to an external surface of the bolt, and a lug extending from an exterior surface of the bolt. The internal bolt cavity is adapted to accept the firing pin and accommodate linear movement of the firing pin with the firing pin lug extending through the bolt slot. The firing pin&#39;s linear movement is relative to the bolt and parallel with the barrel&#39;s bore axis. The bolt is collinear with the bore axis and adapted for linear movement to a charged position, with the linear bolt movement being relative to the barrel and parallel to the barrel&#39;s bore axis. The firearm further comprises a chamber with a cylindrically-shaped ammunition-holding cavity formed within and having a diameter sized to receive a cylindrically-shaped round of ammunition. The ammunition-holding cavity is also collinear with the barrel&#39;s bore axis. The chamber is adapted for linear movement to a charged position, with the linear chamber movement being relative to the barrel and collinear with the barrel&#39;s bore axis. In the charged position, the chamber is positioned rearward of and away from the barrel, and the bolt is also in its charged position with a forward surface of the bolt being generally coplanar with a forward surface of the chamber and the bolt occupying the ammunition-holding cavity. The firearm further comprises a sear. 
   A method associated with this embodiment comprises moving the chamber rearward, away from the barrel and overriding the bolt, until a rearward surface of the chamber contacts the firing pin lug. With the chamber continuing to move rearward, it begins to push on the firing pin lug and push the firing pin rearward toward a rearward end of the bolt cavity, while continuing to override the bolt. The chamber and firing pin continue rearward until a rearward surface of the chamber contacts the bolt lug, at the same time, the forward surface of the bolt is generally coplanar with the forward surface of the chamber, and the firing pin stops moving relative to the bolt. Finally, the chamber and firing pin continue rearward while pushing on the bolt lug and pushing the bolt rearward until the firing pin lug catches on the sear. 
   Yet another embodiment of the present invention provides a method of firing a round of cased telescoped or case-less ammunition from a firearm. The to firearm of this method comprises a barrel having a longitudinal bore axis, a bolt that is collinear with the bore axis and adapted for linear movement between a charged position and a firing position, with the linear bolt movement being relative to the barrel and parallel to the bore axis, and a chamber comprising a cylindrically-shaped ammunition-holding cavity formed therethrough. The ammunition-holding cavity being collinear with the bore axis and having a diameter sized to receive a cylindrically-shaped round of ammunition. The chamber is adapted for linear movement between a charged position and a firing position, wherein the linear chamber movement is relative to the barrel and collinear with the bore axis. In the chamber charged position, the chamber is positioned rearward of and away from the barrel, the bolt is also in its charged position and a forward surface of the bolt is generally coplanar with a forward surface of the chamber, with the bolt occupying the ammunition-holding cavity. In the chamber firing position, a forward surface of the chamber sealingly contacts a rearward surface of the barrel, the bolt is also in its firing position and a forward end of the bolt sealingly contacts a rearward end of the chamber, with the chamber ammunition-holding cavity largely vacated by the bolt. 
   A method associated with this further embodiment comprises placing the chamber and bolt in their respective charged positions, then begins to move the chamber and bolt to their respective firing positions. Introducing a round of cased telescoped or case-less ammunition between the forward surfaces of the chamber and bolt and the rearward surface of the barrel, before the chamber and bolt reach their firing positions. Restraining movement of the round of ammunition along the bore axis, and relative to the barrel, by trapping the round between the forward surfaces of the chamber and bolt and the rearward surface of the barrel. Moving the round of ammunition to be collinear with the bore axis, then moving the chamber toward the barrel to over-ride the round of ammunition. Sealing the chamber against the barrel, and releasing the firing pin to fire the round of ammunition. 
   In another embodiment of the present invention, an ammunition feed system is provided. The system comprises an ammunition container having a path for holding a plurality of cased telescoped or case-less ammunition rounds in a single file manner, and an exit for passing the ammunition rounds out of the container. A cylindrical pusher is positioned in and adapted to freely slide through the ammunition path, with the plurality of ammunition rounds being positioned between the exit and the cylindrical pusher. The cylindrical pusher is also adapted to push the ammunition toward the exit. A feed line is connected to the cylindrical pusher and being of a length to extend through the ammunition path and out of the exit, and having a width to be able to be in the ammunition path without disturbing the movement of the plurality of ammunition. A feed line spool is provided, capable of rotating, and positioned adjacent to the exit and adapted to collect the feed line while rotating. A feed sprocket is also provided, capable of rotating, and attached to and collinear with the feed line spool. The feed sprocket is adapted to turn in unison with the feed line spool and comprises radially spaced teeth. When the feed sprocket rotates, the teeth grip and move the ammunition from the container exit to a firearm associated with the ammunition feed system. 
   A further embodiment of the present invention provides a method of feeding ammunition into a firearm. The method comprises providing a plurality of ammunition rounds in a path, with the path having an exit and a distal end. Pulling a cable through the path containing the plurality of ammunition rounds. Pulling a pusher through the path from the distal end toward the exit by attaching it to the cable, with the pusher being adapted to slide through the path and push the plurality of ammunition rounds toward the exit. When a round of ammunition reaches the exit, presenting the round of ammunition to the firearm. 

   
     BRIEF DESCRIPTION OF THE FIGURES 
     The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
       FIG. 1  is a perspective view of an embodiment of the present invention. 
       FIG. 2  shows a side view of the embodiment shown in  FIG. 1 . 
       FIG. 3  shows a top view of the embodiment shown in  FIG. 1 . 
       FIG. 4  is a cross-sectional side view of the embodiment of  FIG. 1 , shown along line A-A of  FIG. 3 . 
       FIG. 5A  is a perspective view of the weapon of the present invention with the bipod in the stowed position. 
       FIG. 5B  is a perspective view of the weapon of the present invention with the bipod legs and feet extended 
       FIG. 5C  is a side view of the weapon of the present invention, shown with a variety of optional accessories. 
       FIG. 6  is a side cross-sectional view of the lower receiver of the present invention, shown along line A-A of  FIG. 3 . 
       FIG. 7  is a bottom view of the embodiment shown in  FIG. 1 . 
       FIG. 8  is a partially exploded side view of the present invention. 
       FIG. 9  is an exploded view of the internal operating group. 
       FIG. 10A  is a perspective view of the present invention with the barrel handle in the stowed position. 
       FIG. 10B  is a perspective view of the present invention with the barrel handle in the extended position. 
       FIG. 10C  is a perspective view of the present invention with the barrel handle extended and rotated. 
       FIG. 10D  is a perspective view of the present invention with the barrel removed from the receiver. 
       FIG. 11  is perspective view of another embodiment of the present invention, showing the barrel with a collar instead of a handle. 
       FIG. 12A  is a top perspective view showing the charging handle extended. 
       FIG. 12B  is a top perspective view showing the charging handle extended and charged. 
       FIG. 13A  is an end view showing the charging handle arranged horizontally. 
       FIG. 13B  is a top view showing the charging handle offset from horizontal. 
       FIG. 14A  is a side view of the left side cam way. 
       FIG. 14B  is a side view of the right side cam way. 
       FIG. 15A  is a detail of  FIG. 4 , showing the firing assembly in the sear position. 
       FIG. 15B  is a cut-away side view of firing assembly at a second point of the firing cycle. 
       FIG. 15C  is a cut-away side view of firing assembly at a third point of the firing cycle. 
       FIG. 15D  is a cut-away side view of firing assembly at a fourth point of the firing cycle. 
       FIG. 15E  is a cut-away side view of firing assembly at a fifth point of the firing cycle. 
       FIG. 15F  is a cut-away side view of firing assembly at a sixth point of the firing cycle. 
       FIG. 16A  is a cut-away side view revealing the recoil assembly in the sear position. 
       FIG. 16B  is a side cross-sectional view of the recoil assembly. 
       FIG. 17  is a schematic diagram detailing the processes of the firing cycle. 
       FIG. 18  is a schematic diagram detailing the processes of the recoil cycle. 
       FIG. 19  is a perspective view of the linkless ammunition feed system. 
       FIG. 20  is a perspective view of the feed sprocket. 
       FIG. 21  is a cross-sectional view of the ammunition container. 
       FIG. 22  is a top view of the ammunition round of the present invention. 
       FIG. 23  is a cross-sectional side view of the ammunition round of the present invention. 
       FIG. 24  is an perspective and exploded view of the ammunition round of the present invention. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The following description is intended to convey a thorough understanding of the invention by providing a number of specific embodiments and details involving an automatic weapon. It is understood, however, that the invention is not limited to these specific embodiments and details, which are exemplary only. It is further understood that one possessing ordinary skill in the art, in light of known systems and methods, would appreciate the use of the invention for its intended purposes and benefits in any number of alternative embodiments. Throughout the specification, the use of the terms “front” or “forward” refer to the muzzle end of the firearm or toward the muzzle, and the terms “rear” or “rearward” refer to the buttstock end of the firearm or toward the buttstock. 
   Referring to  FIG. 1 , a lightweight, air-cooled, recoil operated machine gun is provided as an exemplary embodiment of the invention. The weapon  100  of the preferred embodiment comprises an upper receiver  200 , a lower receiver  300 , an operating group  400  (shown in  FIG. 9 ), and a linkless-ammunition feed system  500 . 
   Referring now to  FIGS. 1-5C , the weapon  100  comprises an upper receiver  200  and a lower receiver  300 . The upper receiver  200  and lower receiver  300  cooperate to at least partially house the internal operating group  400  within a cavity  150 . The upper receiver  200  comprises an external gripping surface  202  for the operator, left  204   a  and right  204   b  charger ports, an eject gate  208 , and upper  210  and lower  212  rails. 
   Charger ports  204  comprise charger covers  106 . Left and right charger ports  204   a ,  204   b  allow the charger handle  424  to be positioned for ambidextrous use of the weapon  100 . Charger covers  206  provide a barrier limiting the dirt or other contaminants that may otherwise enter the weapon and jam or limit the operation of the internal operating unit  400 . 
   Referring to  FIGS. 5A-C , the upper receiver comprises an upper rail  210  and a lower rail  212 . The rails  210 ,  212  are adapted to provide versatile attachment points for a variety of accessories. Such attachable accessories may include, for example, a forward iron sight  110 , a rearward iron sight  112 , other scopes and sighting and/or aiming systems  113 , a tripod or bipod  220 , bipod mounts  222 , a pintle  118  for mounting to a tripod, grenade launchers  116 , handles  214 , and slings or sling mounts. Upper receiver  200  may also include other means for attaching accessories such as a mount  214  for attaching a handle  114  or other means for mounting the weapon to any appropriate support. 
   In an embodiment of the invention, a bipod  220  is removably mounted to the lower rail  212 . Bipod mount  222  allows bipod  220  to be alternatively moved between a stowed or extended position. In the stowed position, bipod  220  is positioned against a lower portion of the upper receiver  200 . In the extended position, bipod  220  is moved so that the bipod legs  224  are essentially perpendicular to the upper receiver  200 . Bipod legs  224  are extendable and comprise feet  226 , appropriate for stabilizing the forward section of the weapon on a variety of surfaces. Other variations comprise removable and interchangeable feet, allowing the operator to select feet most appropriate for the environment in which the weapon  100  will be deployed. Alternatively, bipod  220  could be permanently mounted to lower rail  212  or another portion of the upper or lower receiver. Such Bipod assemblies are generally known in the art. Other bipod assemblies may be used. 
   Referring now to  FIGS. 7-8 , the upper receiver  200  and lower receiver  300  are hingedly connected at hinge  102  forward of trigger  304 . The hinge  102  may comprise any appropriate hinge assembly as would be apparent to one of skill in the art. The two receivers  200 ,  300  latch together, forming an internal weapon cavity  150 , which houses the internal operating group  400 . 
   When the two receivers  200 ,  300  are unlatched, they pivot about hinge  102 , opening the weapon to allow the operator access to the cavity  150  and internal operating group  400 . The internal operating group comprises a barrel assembly  402 , a firing assembly  404 , and a recoil assembly  406 . Once the two receivers  200 ,  300  are unlatched and opened, the recoil assembly  406  may be removed from the firing assembly  404 , and the firing assembly  404  and the barrel assembly  402  may then be pulled from the firearm upper receiver  200  for maintenance and/or repair. 
   The lower receiver  300  houses the recoil assembly  406  and includes various control features and an ammunition well  310 . The control features comprise a pistol grip  302 , a trigger  304 , a trigger guard  306  and a safing lever  308 . The safing lever may be operable to place the weapon in safe, semi-automatic, automatic, or other firing modes. Such safing levers  308  and mechanisms are generally known in the art. 
   An ammunition container  502  attaches to the ammunition well  310 , which comprises front  314  and rear  316  container guides. Left and right release levers (not shown) allow for removal of container  502  and can be actuated from either side or from both sides of the weapon. 
   As illustrated in  FIG. 6 , embodiments of the lower receiver comprise a buttstock  320  at the rear end of the weapon  100 . The buttstock  320  is movable between a collapsed position  320   a  and an extended position  320   b . The buttstock comprises a fixed portion  322  and a movable portion  323 . The movable portion  323  telescopes with respect to the fixed portion  322 . A pin  324  passes through a groove  327  in the movable portion  323  and engages one of a series of recesses  326  in the fixed portion  322 . The pin  324  is biased into the recesses  326  by a spring  325  and serves to lock the fixed  322  and moving  323  portions of the buttstock  320  at varying degrees of extension. A lever  328  is positioned on the under side of buttstock  320  and the lever  328  moves pin  324  between a locked position in which pin  324  engages one of recesses  326  and a disengaged position in which pin  324  disengages from recesses  326 . Such Buttstock assemblies are generally known in the art, and other Buttstock assemblies may be used. 
   The upper receiver  200  and lower receiver  300  of the preferred embodiment are manufactured from a carbon/epoxy composite. However, the receivers  200 ,  300  could alternatively be manufactured from any suitable material known in the art. 
   Referring now to  FIGS. 9-11D , the barrel assembly  402  comprises a barrel  410 , a barrel handle  412 , and lugs  414 . The barrel  410  is preferably manufactured from Cr—Mo steel with a chromium plated bore. However, the barrel  410  could be manufactured of other materials known in the art. In addition, the barrel  410  preferably has a twist ratio of 1 turn per 9 inches of barrel length. 
   The barrel assembly  402  further comprises a quick-change feature allowing for quick barrel replacement. The preferred embodiment provides for the entire barrel assembly  402  to be quickly and simply removed from and a new assembly re-attached to the weapon  100  in about 10 seconds. The lugs  414  are located at the breech end of the barrel  410 , while the barrel handle  412  is preferably located near the muzzle of the barrel  410 . It should be noted that the handle may be located anywhere along the length of the barrel  410 . When the barrel assembly  402  is attached to the weapon  100 , the barrel is received in the barrel extender  420 , the lugs  414  are mechanically engaged with the barrel extension  420 , and the handle  412  is in its stowed position—generally parallel to the barrel  410 . 
   As illustrated in  FIGS. 11A-11D , to remove the barrel  410 , the operator first extends the handle  412  from its stowed position  412   a  to its extended position  412   b , approximately perpendicular to the barrel  410 , as illustrated by arrow  409 . The operator then rotates the barrel  410  and handle  412  approximately 90° about the longitudinal axis of the barrel  410 , as illustrated by arrow  411 . Rotating the barrel  410  disengages the lugs  414  from the barrel extender  420 , allowing the whole barrel assembly  402  to be detached from the firing assembly  404  and removed from the upper receiver  200 . Barrel replacement takes place in the reverse sequence. 
   During weapon firing, the handle  412  is not in contact with the barrel  410  keeping the handle  412  cool for ease of handling during barrel removal. For operator safety, the barrel may not be removed while the weapon is charged, nor may the weapon be charged unless a barrel is attached. 
   Referring to  FIG. 12 , a variation of the preferred embodiment comprises a concentric collar  418  instead of a handle  412 . The collar  418  is located at the forward end of the upper receiver  200  engages and unlocks the barrel  410 . Turning the collar  418  through a predetermined angle, illustrated by arrow  413 , unlocks the barrel  410  from the barrel extender  420 . Turning the collar  418  through a further angle enables removal of the barrel  410  and collar  418  from the weapon  100 . Again, barrel  410  replacement takes place in reverse sequence. 
   The structure the firing mechanism will now be explained. Referring to  FIGS. 9 , and  12 A- 15 F, some of the major components of the firing assembly include a barrel extension  420 , a chamber  422  having an ammunition holding cavity, a charging handle  424 , a bolt  426 , a firing pin  430 , a firing pin spring  436 , a two-position firing pin latch  438 , forward and rear chamber toggles  440 ,  441 , a toggle rail  444 , a load pawl  446 , a fixed and a movable load pawl cams  450 ,  452 , a sear  454 , a sear link  456 , and a sear spring  458 . 
   The inner surface of the upper receiver  200  comprises cam ways that interact with the internal operating group  400 . The left  444   a  and right  444   b  toggle cam ways provides a path for the toggle cam rollers  442  to follow, a fixed load pawl cam way  450  provides an ammunition loading path for the load pawl pivot arm  448  to follow, and a movable load pawl cam way  452  provides an ejection path for the load pawl pivot arm  448  to follow. The load pawl pivot arm  448  follows the fixed load pawl cam  452  throughout its forward motion as it loads ammunition  120  into the chamber, and follows the movable cam  452  as it moves rearward and ejects a spent shell. The movable load pawl cam way  452  is thus movable between two positions, a by-pass position and an eject position and is biased to the eject position by a spring (not shown). In the by-pass position, the movable cam  452  is pivoted upward due to the forward movement of the load pawl pivot arm  448 . In the eject position, the movable cam  452  is lined up with the fixed cam  450 , and provides a path for the load pawl pivot arm  448  to follow when it ejects a spent shell. The interaction between the rollers and cam ways are discussed in greater detail herein. 
   The forward  440  and rear  441  chamber toggles are hingedly connected to each other. The rear chamber toggle  441  is also hingedly connected to the barrel extension  420 , and the forward chamber toggle  440  is hingedly connected to the chamber  422 . The rear chamber toggle  441  comprises a roller  442 , which rides in a toggle rail or cam  444 . The toggle rail  444  is attached to the upper receiver&#39;s internal surface  201 , and fixed relative to the other components of the firing assembly  404 . In addition, it is contemplated that the toggle rail  444  may be integrally formed with or permanently or removably attached to the interior surface  201 . As the firing assembly  404  moves through the firing cycle, the fixed toggle rail  444  controls the position of the toggles  440 ,  441 , which, in turn, controls the position of the chamber  422  relative to the barrel extension  420 . The load pawl  446  is also hingedly connected to the barrel extension  420  and comprises a roller. The load pawl pivot arm  448  rides in both a fixed load pawl rail  450  and a movable load pawl rail  452 . The load pawl cams  450 ,  452  are attached to the upper receiver to interior surface  201 . The fixed load pawl cam  450  may be integrally formed with or permanently or removable attached to the interior surface  201 . The chamber  422 , bolt  426 , firing pin  430  are concentric with each other and are all collinear with the barrel  420 . In addition, the bolt  426  is fixed relative to the barrel  410 , eliminating the need for any complex locking mechanism. 
   The operating cycle of the weapon begins with charging the weapon. Referring specifically to  FIGS. 12A-12B , charging the weapon  100  for firing, first requires the operator to extend the charging handle  424  from a stowed position to a ready position (arrow  425 ,  FIG. 12A ). The charging handle  424  is then pulled rearward, toward the buttstock  320  (arrow  427 ,  FIG. 12B ). Referring to  FIGS. 15A-16A , as the charging handle  424  is moved rearward, the eject port is opened (not shown), the recoil spring  462  is compressed, and the entire firing assembly  404  is moved to the sear position and latched in place by the sear  454  (see  FIG. 15A ). In the sear position, the toggles  440 ,  441  are folded, holding back the chamber  422 , which creates a clearance between the barrel  410  and the chamber  422 . This clearance provides an opening for the next round of ammunition  120 , which will eventually move upward from the magazine  200  to be parallel and linear with the barrel  410  and chamber  422 . 
   As shown in  FIGS. 13A-13B , the charging handle  424  can be alternatively positioned on either the right or left side of the weapon for ambidextrous use. In a preferred embodiment, the charging handle  424  is positioned at an angle a approximately fifteen degrees above horizontal. This provides additional clearance  424   c  between the handle  424  and ammunition container  200  ( FIG. 13B ). Alternatively, the charger handle  424  may extend horizontally from the weapon ( FIG. 13A ). 
   With the weapon  100  charged, it is now ready to fire. The weapon firing cycle may be best understood in relation to  FIGS. 14A-15F . 
   In  FIG. 15A , the firing assembly  404  is in the sear position and the weapon is ready to fire. In the sear position, the firing assembly  404  is held back by the sear  454  and the firing pin  430  is held in a first sear position by the two-position firing pin latch  438 . The toggles  440 ,  441  are held in a bent configuration by the toggle rail  444  (see  FIG. 15B ), thus holding back the chamber  422 . The chamber  422  butts against a bolt lug  427  and a firing pin lug  432  and is completely occupied by the bolt  426 . To fire the weapon  100 , the operator releases the firing assembly  404  from the sear position by pulling the trigger  304 . This movement pivots the trigger  304 , pushing the sear link  456  upward, which then pivots the sear  454  to release the firing assembly  404 . Now released, the firing assembly  404  begins to move forward under force of the recoil spring  462 . This forward movement pushes the load pawl  446  under the next ammunition round  120  and begins to push the barrel  410  forward with respect to the upper receiver  200 . The slides relative to the upper receiver in barrel extension tracks  445 . 
   Referring to  FIG. 15B , the firing assembly  404  continues forward, pushing the load pawl pivot arm  448  along the fixed load pawl rail  450 , which causes the load pawl  446  to pivot upward. As the load pawl pivot arm  448  follows the fixed load pawl rail  450 , it pushes on the bottom of the movable pawl rail  452  to pivot it upward to its by-pass position and out of the path of the forward moving load pawl pivot arm  448 . Once the load pawl pivot arm  448  clears the moving rail  452 , the moving rail  452  drops back down to its eject position. This movement begins to lift the round  120  from the top of the ammunition magazine  200 . Once the round  120  is out of the container, the firing assembly has progressed far enough for the firing pin latch  438  to engage in a firing pin cam (not shown). The cam pivots the firing pin latch  438  from a first position to a second position, releasing the firing pin  430 . The firing pin  430  is now able to proceed under the force of the firing pin spring  436 . However at this point, the firing pin  430  is still prevented from proceeding forward by contact between the firing pin lug  432  and the chamber  422 . 
   The chamber  422  is preloaded forward by the firing pin spring  436 . Accordingly, as the load pawl  446  lifts the round  120  upward, the forwardly biased chamber  422  traps the round  120  between the vertical surfaces of the chamber and the barrel. This orients the round  120  parallel with the chamber and barrel while the load pawl continues to push the round upward until the round is co-linear with the chamber and barrel. 
   Referring now to  FIG. 15C , the firing assembly  404  continues forward and the load pawl  446  continues to pivot upward, placing the round  120  collinear with the chamber  422  and barrel  410 . Also at this time, the toggle rollers  442  are guided by the toggle rail  444 , rotating the rear toggles  441  about axis  441   a , which then causes the forward toggles  440  to rotate about axis  440   a . This motion straightens the toggles  440 ,  441  at the connecting joint  439  and pushes the chamber  422  forward. The forward moving chamber  422  simultaneously takes up the clearance between itself and the barrel  410  and pushes past the bolt  426 , overriding the round  120 . In this manner, the chamber  422  is continuously occupied by either the bolt  426  or an ammunition round  120 , and foreign debris is prevented from entering the chamber  422 . 
   At the same time, this movement also creates clearance between the chamber  422  and the firing pin lug  432 , allowing the firing pin spring  436  to push the firing pin  430  forward. As the firing pin  430  moves forward, the firing pin lug  432  engages the firing pin latch  438  at the second sear position  438   b . The firing pin cam (not shown) interlocks with the pin latch  438  to prevent release of the firing pin  430  until the chamber  422  is closed. As the chamber  422  closes, it overrides the round  120  while the load pawl  446  drops slightly to clear the chamber  422 . 
   In  FIGS. 15D and 15E , the chamber  422  has closed and the assembly  404  continues forward. The firing pin cam further pivots the firing pin latch  438 , releasing the firing pin  430  from the second sear position  438   b . The firing pin  430  moves through the bolt slot  428  and impacts the cartridge primer  128  (see FIG. A), which ignites the cartridge propellant  130  creating a high-pressure gas to send the bullet  122  down and out of the barrel  410 . The recoil force generated by the discharge of the round  120  pushes the firing assembly  404  rearward. 
   In  FIG. 15F , the firing assembly  404  moves rearward. The toggles rollers  442  are guided by the toggle rail  444 , rotating the rear toggles  441  about  441   a , which then causes the forward toggles  440  to rotate about  440   a . This motion bends the forward and rear toggles  440 ,  441  at the connecting joint  439  and pulls the chamber  422  open, away from the barrel  410  and back over the bolt  426 . As the chamber  422  continues rearward, it contacts the firing pin lug  432  and pushes it back to the rear sear position  438   a . A firing pin latch spring (not shown) biases the firing pin latch  438  upward, which secures the firing pin latch  438  once the lug  432  is in the rear position. 
   At the same time, the load pawl pivot arm  448  moves rearward into movable load pawl rail  452  to carry the load pawl through its ejection path. The movable load pawl rail  452  pivot is above the load pawl  446  pivot which causes the movable load pawl rail  452  to remain fixed due to a down rotational stop. The moveable rail  452  guides the load pawl  446  through a greater range of motion than the fixed cam  450 , sweeping the load pawl  446  upward and ejecting the spent cartridge casing  126 . After the spent cartridge  126  is ejected through the ejection port, which is open on charging, the load pawl rotates back down its initial sear position. As the firing assembly  404  continues rearward, the load pawl  446  moves past the ammunition well  310 , allowing room for another round  120  to be presented from the magazine  502 . 
   While the firing cycle has been described at six discrete points relating to  FIGS. 15A through 15F , these six positions have been described for illustrative purposes only. It should be understood that, in operation, the present invention&#39;s firing cycle comprises a smooth and continuous sequence of motion, taking the firing assembly from sear position, to firing the round, and back to sear position. 
   Referring to  FIGS. 16A and 16B , the velocity and travel distance of the barrel  410  and firing assembly  404  during recoil is regulated by the impulse averaging recoil system  406 . The impulse averaging system comprises a recoiling mass, which is comprised of the mass of the moving parts of the internal operating group  400  (see  FIG. 8 ), a drive spring  462  and a dashpot or damper  464 . 
   The damper  464  is connected between the lower receiver  300  and the firing assembly  404  and contained within the buttstock  320  and the upper receiver internal cavity  150 . The damper  464  comprises a spring retainer  330 , a piston rod  331 , and a buffer body  332 . The spring retainer  330  is a long cylindrical tube with an open rear facing end and a closed forward end. The buffer body  332  is a cylinder with a forward end sealed by a forward end cap  333 , and a rearward end sealed with a rear end cap  334 . A shock tube  335  is contained within the buffer body  332  and is retained collinear with the buffer body by the forward and rear end caps. The buffer body  332  and shock tube  335  assembly is telescopically received in the open end of the spring retainer  330 . The forward end cap comprises a forward shuttle valve  336  and valve spring  337 , and the rearward end cap comprises a rearward shuttle valve  338  and valve spring  339 . The rear end cap further releasably secures the recoil assembly to the buttstock. The spring retainer and the rear end cap comprise flanges  340  that retain the drive spring. 
   The buffer body and shock tube comprise hydraulic fluid. The shock tube further comprises a series of orifices  341  in its circumferential side that allow the hydraulic fluid to pass from the shock tube to the buffer body and vice versa. The piston rod  331  extends through an opening in the closed end of the spring retainer  330 , through a sealed opening in the forward end cap  333  and into the shock tube  332  and past the open end of the spring retainer  330 , terminating in a piston head  344 . The piston rod  331  has a forward end that comprises two flanges. A first flange  342  releasably secures the recoil assembly to the barrel extension and a second flange  343  prevents the piston rod from extending too far into the spring retainer. 
   The damper  464  acts as a velocity regulator that controls the forward velocity of the firing assembly  404 , and ensures that the weapon fires at a consistent forward velocity. The damper  464  controls the peak load on recoil by monitoring the recoil velocity and providing more resistance if the velocity is high and less if the velocity is low. The recoil system  406  of the present invention allows the weapon  100  to be fired at any attitude (+/−90° and with a large friction or impulse variation from the round  120 . 
   When the weapon is charged, the recoil assembly is compressed, the spring  462  is compressed, the shock tube  335  and buffer body  332  are pushed into the spring retainer, and the piston rod  331  is deeply extended into the shock tube  335 . This orientation places a high percentage of the hydraulic fluid forward of the piston rod head  344  and little to no hydraulic fluid rearward of the piston rod head. When the trigger is pulled, the main spring  462  pushes the spring retainer  330 , piston  344 , and barrel extension forward. While moving forward, the piston pushes on the hydraulic fluid. The bulk of the hydraulic fluid moves from forward of the piston head  344  through the shock tube orifices  341  axially along the outer surface of the shock tube, between the shock tube  335  and buffer body  332 , and back into the shock tube through more orifices, rearward of the piston head. 
   As the piston moves forward, there are fewer and fewer orifices for the piston to push hydraulic fluid through, this results in a gradual reduction of flow area controlled by the fixed orifices. Also, the spring loaded shuttle valve  336  in the forward end cap  333  initially remains open presenting a large flow area. When the differential pressure across the valve exceeds the spring pressure, the shuttle valve  336  closes to greatly reduce the flow area. The combination of reduction of the fixed orifices and the shuttle valve orifice closing, creates greater resistance to fluid flow and therefore a greater resistance to the forward motion of the barrel extension. The fixed orifices  341  and the shuttle valve  336  and spring  462  are designed such that the forward momentum of the barrel extension remains constant, independent of external forces such as gravity or increase mechanical resistance such as friction. 
   Once the weapon fires, the barrel extension moves rearward driven by momentum of the fired round minus the forward motion momentum. The piston  344  once again pushes the hydraulic fluid. The bulk of the hydraulic fluid moves from rearward of the piston head through the fixed orifices  341  axially along the outer surface of the shock tube  335 , between the shock tube and buffer body  332 , and back into the shock tube, through more fixed orifices  341 , forward of the piston head. As the piston moves rearward, there are fewer and fewer orifices for the piston to push hydraulic fluid through, this results in a gradual reduction of flow area controlled by the fixed orifices. The rear spring loaded shuttle valve  338  in the rearward end cap  334  initially remains open presenting a large flow area. When the differential pressure across the valve exceeds the spring pressure, the shuttle valve closes to greatly reduce the flow area. The combination of reduction of the fixed orifices and the shuttle valve orifice closing, creates greater resistance to fluid flow and therefore a greater resistance to the rearward motion of the barrel extension. The fixed orifices  341  and the shuttle valve  338  and spring  462  are designed such that the rearward momentum of the barrel extension remains constant, independent of external forces such as gravity or increase mechanical resistance such as friction. It also is design to minimize the load to approximately 33 lbf with a large range of ammunition round impulse variation. Additional embodiments of recoil systems are described in U.S. Pat. Nos. 6,343,536 and 6,644,168, each of which is hereby incorporated by reference in its entirety. 
     FIG. 17  is a diagrammatic representation of the counter recoil cycle as the operating group moves from the fully retracted, ready to fire, Sear position to the fully forward Fire position.  FIG. 18  shows the recoil cycle as the operating group moves from the fully forward, Fire position to the fully retracted, Sear position. Assuming that the Sear position defines the origin of movement or zero position, in a preferred embodiment, the steps of the counter recoil cycle occur at approximately the following distances from the Sear position: Sear at 0.0 in.; Begin Lift at 0.65 in.; Begin Chamber Closure at 0.65 in.; Capture Round at 0.75 in.; End Lift at 1.15 in.; End Chamber Closure at 2.05 in.; Begin Firing Pin Drop at 2.29 in.; and Fire at 2.3 in. The steps of the recoil cycle occur at approximately the following distances from the Sear position: Fire at 2.3 in.; Begin Chamber Opening 2.05 in.; Begin Indexing at 1.3 in.; End Opening at 1.15 in.; Begin Eject at 1.1 in.; End Eject Round at 0.5 in.; and Sear at 0.0 in. Alternatively, these distances can be adjusted or rearranged in accordance with the knowledge of one skilled in the art. 
   In the embodiments described herein, the rounds enter the cycle from the bottom and exits from the top. Unlike known weapons where one round must be removed before the next round can be fed, feeding a round into the weapon will force out any rounds remaining in the breech opening. This prevents multiple feed issues during misfires and immediate action. A misfire requires only recharging the weapon which positively clears the round out of chamber and the feed path. These features provide a more reliable weapon in the field and easier operator training. 
   Referring now to  FIGS. 19-21 , the preferred embodiment further comprises a linkless ammunition feed system  500 . The ammunition feed system  500  comprises an ammunition container  502 , a feed sprocket assembly  504 , and a feed actuation assembly  506 . 
   In the preferred embodiment, The ammunition container  502  is a two-piece design having a front portion  508  and a rear portion  510 . Container sidewalls  512  may be integrally formed with either the front  508  or rear  510  portions, or both. The ammunition container  502  has a capacity of 150 rounds of ammunition, though higher or lower capacities containers  502  are possible. The container  502  may be made from glass and PTFE filled nylon or other appropriate material. A translucent or clear material preferably forms the rear portion  510 , allowing the operator to view the number of rounds remaining in the container. 
   The ammunition container  502  further comprises parallel front and rear interior surfaces  514 ,  516 , with one or more interior walls  518  extending orthogonally between the front and rear interior surfaces  514 ,  516 . A space is provided between the interior walls  518  to form an ammunition path  520 . In the preferred embodiment, the interior walls  518  cooperate to form a single, convolute ammunition path  520  beginning at some position within the container  502  and terminating at a discharge opening  522  and feed sprocket assembly  504 . Embodiments of the ammunition path  520  extend in a generally spiraling coiled layout with no sharp turns or corners. However, the ammunition path  520  can be configured in any shape or layout that allows the ammunition to freely feed through the path  520  as the weapon  100  is fired. The ammunition container  502  also comprises a discharge opening  522  to allow the ammunition rounds  120  to pass from the ammunition container  502  into the cavity  150  created by the upper and lower receivers  200 ,  300  for presentation to the load pawl  446 . 
   The feed sprocket assembly  504  is attached to the ammunition container at the discharge opening  522  and comprises a feed sprocket  524 , a drive wheel  526 , a back drive wheel  528  and pawl  530 , a spool  532 , and a feed cable  534 . The feed sprocket  524 , drive wheel  526 , back drive wheel  528  and pawl  530 , and spool  532  are linearly arranged and rotate about the same axis of rotation  504   a , and also rotate in unison. The spool  532  acts as a spool to collect the feed cable  532 . The feed sprocket  524  and back drive wheel  528  are positioned at one end of the spool  532 , while the drive wheel  526  is positioned at the opposite end. The feed cable  534  is preferably made of steel or another material of appropriate strength. One end of the cable  534  is attached to a cylindrical pusher (not shown), which pushes the ammunition rounds  120  through the ammunition path  520  as the feed cable  534  is taken-up by the spool  532 . The feed cable  534  collects on the spool  532  in a single layer to prevent pitch change. This ensures that one of rotation of the spool  532  will consistently correspond to a linear displacement of a single round of ammunition  120 , regardless of the location of the last round within the ammunition path  520 . This also ensures that the feed sprocket  524  is continually supplied with the next available round  120 . The feed cable is threaded from the spool  532  through the ammunition path  520  on the outside of the rounds  120 . As the cable  534  is fed through the ammunition path  520  during firing cycles, the rounds  120  serve as low friction bearings allowing the cable to turn the corners in the ammunition container and not bind. 
   As the drive wheel  526  rotates, the feed sprocket  524  and spool  532  also rotate, winding the feed cable  534  about the spool  532 . As the feed cable  534  is taken up on the spool  532 , it pulls the cylindrical pusher through the ammunition path  520 . The cylindrical pusher pushes all preceding rounds of ammunition through the ammunition path toward the discharge opening  522  and feed sprocket  524 . Thus, eliminating the need to link the rounds of ammunition together. As each individual round of ammunition  120  approaches the feed sprocket  524 , the teeth of the sprocket  524  engage the round  120 . As the sprocket  524  continues to rotate, it lifts the round  120  into the receiver cavity for presentation to the load pawl  446 . The back drive wheel  528  and back drive pawl  530  ensure that the feed sprocket  524  and spool  532  will not reverse rotation during the weapon firing cycle. 
   The feed system  500  also comprises a driving slide  536  and pushrod  540 . The pushrod  540  is slidably attached to the ammunition container  502  and is to biased in an extended or up position by a return spring (not shown). The pushrod  540  comprises a pawl to engage with and turn the drive wheel  526 . 
   The driving slide  536  is an elongated member, with a first end  536   b  pivotally connected to the interior surface  201  of the upper receiver  200  and a second, distal end  536   a . The driving slide  536  further comprises a tappet  538  on its underside, at the distal end  536   a . The length of the driving slide is sufficient that the distal end  536   a  and tappet  538  move in a generally linear and vertical fashion when the slide  536  pivots. 
   When the driving slide  536  and pushrod  540  are in their initial position, they are biased upward by the spring  544 . As the firing assembly  404  moves rearward during the recoil or while the weapon is being charged, a feed system cam or roller on the barrel extension  420  engages with the driving slide  536  to force it to pivot, moving the tappet  538  downward. The tappet  538  forces the pushrod  540  down, compressing the return spring  544 . As the pushrod  540  is driven down, the drive pawl  542  engages and turns the drive wheel  526 , which sets the spool and feed sprocket in motion as described herein, presenting a round  120  to the load pawl  446 . 
   With the weapon  100  now in the sear position, the trigger  304  is pulled (or if the trigger  304  remains pulled when the weapon is in its automatic setting) and the firing assembly  404  moves forward, the feed system cam/roller moves away from the driving slide  536 , allowing the return spring  544  to return the pushrod  540  and driving slide  536  to their initial position. This also places the drive pawl  542  in a position to turn the drive wheel  526  during the next cycle. Another variation provides the driving slide  536  with a spring to assist in returning it to its initial position. 
   It should be noted that the weapon  100  is also capable of utilizing a number of different ammunition containers  502 . An alternative embodiment comprises a conventional, single column, ammunition magazine capable of holding twenty-five ammunition rounds  120 . 
   As illustrated in  FIGS. 22-24 , a preferred embodiment of the weapon utilizes a substantially cylindrical ammunition round  120 . The round  120  comprises a bullet or ball  122 , a forward cap  124 , a cartridge case  126 , a primer  128 , a propellant charge  130 , a primer retainer  132 , a retainer ring  134 , and a stand-off spacer  136 . 
   It will be apparent to those skilled in the art that various modifications and variations can be made in the method of manufacture of the present invention and in construction of this automatic recoil operated weapon without departing from the scope or spirit of the invention. Embodiments of the invention are intended for use in multiple weapon configurations utilizing various ammunition calibers and fulfilling a variety of purposes. For example, possible configurations include, but are not limited to, light machine guns, long and short automatic rifles, and carbines. 
   Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification be considered as exemplary only.