Abstract:
The invention relates to firearms and especially shotguns as well as devices or mechanisms for reducing felt recoil. In particular, the invention relates to a gas-operated device to reduce felt recoil using a recoil suppressing mass, or recoil mass, to create a counter-acting force to the recoil force. The recoil mass moves in response to the gas pressure in the barrel after firing, and more particularly the control of the flow of gas into a chamber to force the recoil mass to move and generate a recoil suppressing force. In one aspect, incorporating the gas-operated device in a firearm can improve the operator&#39;s control of the firearm and measurably reduces felt recoil and/or muzzle climb

Description:
REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority benefit of U.S. provisional application 61/025,608, filed Feb. 1, 2008, the entire contents of which are incorporated herein by reference. 
     
    
     FIELD OF INVENTION 
       [0002]    The invention relates to firearms and especially shotguns as well as devices or mechanisms for reducing felt recoil. In particular, the invention relates to a gas-operated device to reduce felt recoil using a recoil suppressing mass, or recoil mass, to create a counter-acting force to the recoil force. The recoil mass moves in response to the gas pressure in the barrel after firing, and more particularly the control of the flow of gas into a chamber to force the recoil mass to move and generate a recoil suppressing force. In a shotgun, and especially a semi-automatic or automatic shotgun, the recoil forces are notoriously high and the incorporation of the devices of the invention can provide dramatic improvement to the safe or efficient handling of a firearm. In one aspect, incorporating the gas-operated device in a firearm can improve the operator&#39;s control of the firearm and measurably reduces felt recoil and/or muzzle climb. 
       BACKGROUND FOR AND INTRODUCTION TO THE INVENTION 
       [0003]    The operating mechanisms found on current firearms, although reliable and widely employed, nevertheless suffer from a number of deficiencies. The recoil forces generated with some firearms essentially renders them unsatisfactory from an accuracy and muzzle climb perspective. Notable examples of rifles that cannot be controlled in automatic mode as compared to semi-automatic mode exist. 
         [0004]    For shotguns in particular, a gas pressure loader for semi-automatic operation has been used for some time. These semi-automatic shotguns generally require a defined gas pressure and an easily removable, rugged cartridge shell. With modern, powerful cartridges that are metal with a long sleeve and a shell body made of plastic, the gas pressure loader shotguns enjoy relatively trouble-free operation. However, the recoil forces generated by shotguns is typically quite high even in the semi-automatic mode. 
         [0005]    In general and in one aspect, the invention addresses the design of firearms by providing a new gas pressure operated device to generate a counter-acting force that acts to suppress at least part of the recoil forces generated upon firing. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention addresses the problems and disadvantages associated with conventional firearms and weapon systems and provides improved devices for reducing recoil effects in a variety of firearms. 
         [0007]    In one particular embodiment of the present invention, a recoil control device for use in a firearm comprises a bolt configured to alternate between a forward position and a rearward position in response to the firing of one or more cartridges. The firearm includes a barrel and a counter recoil assembly having a recoil mass chamber and recoil mass. The barrel comprises a first gas port capable of transmitting or communicating gas from the barrel into a recoil mass chamber, where the recoil mass chamber has an internal moving recoil mass that moves in reaction to gas pressure communicated from the barrel. The barrel may also comprise a second gas port in communication with an action piston tube, optionally through a gas manifold, the tube having an action piston and a bolt carriage rod linked to the bolt assembly to move the bolt from a forward position to a rearward position in reaction to gas pressure in the barrel. Through these components the firing of the firearm creates a counter recoil force generated by the movement of the recoil mass in response to gas pressure through the first gas port. The counter recoil force actually suppresses the felt recoil and can reduce muzzle climb and can improve the handling of the firearm. While a preferred arrangement of the recoil mass chamber places it near the barrel, as shown in the Drawings, another preferred arrangement places the recoil mass chamber in or at least partially within the stock of the firearm. In this and any embodiment of the invention, the first gas port from the barrel can transmit gas pressure to a recoil mass chamber through one or more tubes, a gas manifold or gas block, a system of tubes, or other means of gas communication. As referred to here and throughout this disclosure, a first gas port can refer not only to a single gas port in the barrel, but multiple gas ports located at essentially the same position on the length of the barrel. Thus, the first gas port can refer to the relative timing of the gas pressure entering the first gas port or transmitted from the gas port as compared to the timing of the gas pressure entering or being transmitted from a second gas port, if a second gas port is used. As described below, the arrangement, number, size, shape, and exit angle of the gas port(s) used in any embodiment can be varied and the depictions in the Figures are merely exemplary of the gas ports and gas manifolds or gas blocks that can be used or located on a firearm. Combinations of shapes and sizes and exit angles of gas ports can also be used in a single firearm design. 
         [0008]    In a more specific embodiment of the invention described above, a semi-automatic or automatic shotgun can be designed according to the invention. In this aspect, the firearm or shotgun comprises a barrel having an internal bore with a breech at its rearward end and having one or more gas ports at a location along the bore, the gas port in communication with a gas manifold. As in conventional shotguns into which the invention can be adapted, the shotgun can include a receiver having a stock section and a cartridge chambering section, as well as an ejection port and a feed tube. In an optional embodiment of a shotgun, the invention includes a stock loading feed tube or magazine. The shotgun can use conventional gas-operated bolt assemblies, such as one having at least one action piston tube in communication with a gas manifold, or other source of pressurized gas from the barrel, and a rod assembly extending from an action piston in the action piston tube, the rod operably driven by the action piston to move the bolt assembly in the rearward direction, and a return spring to move the bolt assembly in the forward direction to load a successive round. Generally, the bolt and carriage assembly has a guide or track region supporting a moving bolt, and the bolt and carriage assembly define a cartridge receiving space on the receiver. A rotating bolt face can be used to engage the cartridge and the bolt face may have an aperture for a firing pin, the bolt face rotating during the backward and forward movement of the bolt assembly. In this or any aspect of the invention, the recoil mass chamber is in communication with the above-mentioned gas manifold and the chamber can be positioned along the barrel or parallel to the barrel, although other arrangements are possible. This recoil mass chamber contains and controls the movement of a recoil mass, which moves, typically but not limited to a rearward movement toward the chambering end of the barrel, in response to gas pressure in the barrel after firing. The counter forces generated by the movement of the recoil mass suppress the felt recoil forces in response to the impulse from firing the firearm. Incorporating the moving recoil mass in communication with the pressurized gas transmitted from the barrel in this way advantageously uses the energy from firing each round to improve the performance of a firearm. 
         [0009]    In any firearm or shotgun embodiment of the invention, the gas pressure utilized in a gas manifold, gas communication tubes or gas connector or transmission tubes, or other tubes or conduits for transmitting gas pressure from the barrel as described throughout this disclosure, can be optionally regulated. Various gauges, bleed ports, vents, regulators, valves, or tube design or construction options are available for regulating the pressure and even the timing of the gas transmission. 
         [0010]    In any firearm or shotgun embodiment of the invention, an electronic trigger and firing system can optionally be used, including a trigger, a battery or power supply, a mechanical switch actuated by an electrical signal from the trigger to actuate the movement of a firing pin, and a firing pin. Conventional mechanically driven firing pins linked to a trigger, sear, and hammer as used in various other firearms can also be used. The choice of the firing mechanism and its parts is not especially important in making and using the counter recoil systems and apparatus of the invention. 
         [0011]    In any embodiment of the invention, the path of the recoil mass in response to the impulse from gas pressure can be varied from that shown in the drawings. The recoil mass can move along a path defined by its chamber, which may include internal tracks, rollers, or guides. Thus, a straight path toward the anterior of the firearm, a curved or curvi-linear path, a path extending outward from the barrel, a path moving inward toward the barrel, and a path crossing over the barrel can possibly be selected. Furthermore, multiple recoil masses in multiple chambers can be used if desired. The path chosen and the recoil mass shape and design relates to the design characteristics of a particular firearm. The recoil forces can be further controlled or managed through the positioning of the barrel of the firearm relative to the grip or stock of the weapon. While not depicted in the drawings, embodiments with more than one recoil mass within one recoil mass chamber can also be used. Combinations of recoil mass chambers and recoil mass designs and numbers with multiple chambers for each barrel are also possible. 
         [0012]    In any embodiment of the invention, the recoil mass chamber can be a closed or sealed tube except for the input of pressurized gas transmitted or communicated from the barrel and a pressure release or bleed valve. The bleed valve can be adjustable or regulated by the user in order to optimize the performance of the firearm, and one or more gauges to monitor gas pressure or peak gas pressure at various points can be incorporated into the system. The bleed valve allows the pressure in the recoil mass chamber to be released during the action of the firearm. The location of the bleed valve is not critical, but it may optionally be placed at the rearward end or back of the gun end of the chamber. Similarly, the action piston tube can be a closed or sealed tube except for the input of pressurized gas and a pressure release or bleed valve. The pressure release or bleed valve can be regulated or adjusted by the user and again one or more gauges can be incorporated for this purpose. Again, the position of the bleed valve in the action piston tube is not critical, but it can be located at the rearward end. 
         [0013]    The devices, mechanisms and aspects of the invention can be used to complement or improve existing or conventional firearms and can be combined with various arrangements, attachments, and combinations, including without limitation internal lock and release systems, loading systems, ejection systems, gas injection systems, recoil reduction stock devices and systems, muzzle brakes, directional barrel ports, sighting systems, tripods, mounting systems, and firing mechanisms. 
         [0014]    In one general aspect, the invention comprises a counter recoil device that employs the gas pressure from the barrel to create a counter recoil force by generating the sudden movement of one or more recoil masses. Generally, as noted above, the recoil mass or masses are confined within one or more closed chamber or chambers, but other configurations with partially closed chambers can be used. The counter recoil force is generally timed to reduce the total felt recoil forces, as can be seen in the graph of  FIG. 5 . While time periods immediately after or as soon as possible after the percussion or initial impulse from firing may be desired, other time periods for generating the counter recoil forces can be selected. Optionally, recoil mass movement within about 0.0005 seconds, or about 0.0025 seconds, or about 0.005 seconds from the detection of the initial filing impulse as felt recoil (see  FIG. 5 ) is preferred in order to reduce recoil levels substantially. Furthermore, multiple recoil masses can generate counter forces simultaneously or even at different time points compared to the initial impulse of firing. Accordingly, the reduction in felt recoil predicted by  FIG. 5  can be exceeded in certain designs to provide 50%, 60%, 70%, 80%, or even 90% reduction in felt recoil. While no specific level of felt recoil reduction is required, it is generally understood that about 20% or more reduction in felt recoil can be generated by the use of the suppressive recoil force provided by the invention. 
         [0015]    The recoil suppression device can be manifested as in one of the Figures accompanying this disclosure. Also, numerous embodiments and alternatives are disclosed in the accompanying claims. In another aspect, the invention provides a method for making a counter recoil device of the invention and/or incorporating into a firearm a counter recoil device comprising one or more recoil masses as described here. 
         [0016]    Other embodiments and advantages of the invention are set forth in part in the description that follows, and in part, will be obvious from this description, or may be learned from the practice of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    For a more complete understanding of the invention and some advantages thereof, reference is now made to the following descriptions taken in connection with the accompanying drawings in which 
           [0018]      FIG. 1  is a side view of an exemplary shotgun of the invention, where the dotted lines indicate internal elements. 
           [0019]      FIG. 2  depicts a frontal view of an exemplary shotgun, looking into the barrel. 
           [0020]      FIGS. 3   a - d  depict the movement of particular parts and the counter recoil device during the operation of an exemplary firearm. 
           [0021]      FIG. 4  depicts specific elements of an exemplary counter recoil device of the invention. 
           [0022]      FIG. 5  shows a graph of the recoil forces (Force v Time) from a simulated firing of a shotgun cartridge using the counter recoil device of the invention. 
           [0023]      FIG. 6  depicts a schematic side view of various elements of an exemplary counter recoil system or device of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0024]    The incorporation of the novel recoil controlling device of the invention onto a rifle, firearm, and particularly a shotgun can dramatically reduce felt recoil and/or muzzle climb during operation. Especially with semi-automatic and automatic firing modes, muzzle climb can adversely effect accuracy in firing. In the testing of an exemplary embodiment, the use of the counter-acting recoil device results in about 37-40% reduction of felt recoil as calculated at the shoulder of a hypothetical operator as compared to firing when the counter-acting recoil system is not operating. Further data can be expressed as degrees of muzzle climb measured in a standard Ransom International (Prescott, Ariz.) firearm rest versus time under similar conditions for a firearm. 
         [0025]    As discussed, one preferred embodiment of the invention is a shotgun incorporating a counter recoil force-generating device, as generally depicted in  FIG. 1 , where the bolt assembly ( 110 ) is in line with the barrel ( 100 ). Charging handle ( 116 ) connected to bolt assembly is used to cock firearm and can optionally incorporate a folding external handle. A recoil suppressive mass chamber ( 190 ) can be positioned directly below the barrel ( 100 ). One or more gas port blocks at ( 150 ) or manifolds in the barrel are in communication with a gas manifold ( 154 ) that directs the pressurized gas from the barrel ( 100 ) into the recoil mass chamber ( 190 ). A threaded assembly knob ( 140 ) can be used to disassemble the firearm, as in conventional shotguns. A preferred design incorporates a magazine or feed tube in the stock as shown at ( 130 ). 
         [0026]      FIG. 2  shows a front view of the shotgun in  FIG. 1 , where charging handle ( 116 ), barrel ( 100 ), recoil suppressive mass chamber ( 190 ), and bolt carriage piston tube ( 170 ) are shown in relation to each other. 
         [0027]      FIGS. 3   a - 3   d  depict the operation of the recoil suppressive mass ( 160 ) in a firearm. In  FIG. 3   a , the recoil mass ( 160 ) is at its resting position at forward end of the chamber ( 190 ). The recoil spring ( 192 ) in chamber ( 190 ) is depicted in  FIG. 3   a  but not shown in other views. The cartridge ( 120 ) is in a cocked and loaded position with casing of cartridge ( 121 ) against bolt face ( 114 ). Bolt assembly ( 110 ) incorporates a firing pin as in conventional firearms, but optionally, as discussed below, employs an electronic control of the movement of the firing pin (not shown here). A first gas port block ( 150 ) having one or more gas ports ( 158 ) from the barrel ( 100 ) into the gas block ( 150 ) is at a first position, near rearward end of barrel ( 100 ). One or more gas connector tubes ( 152 ) connect first gas block ( 150 ) to gas manifold ( 154 ). Gas manifold ( 154 ) can be an integrated part, as shown here, to hold chamber ( 190 ) by its circular region and connect it to barrel ( 100 ) by welded connection, for example. Conventional bolt carriage system, with tube ( 170 ), rod ( 180 ) and piston ( 172 ) that move in response to gas pressure to release bolt assembly and push it rearward are also incorporated. At forward end of chamber ( 190 ) is an optional recoil mass buffer ( 162 ) to reduce impact force of recoil mass ( 160 ) in its return movement pushed by recoil spring ( 192 ). The buffer can itself be a spring, an elastic material, or a fluidic system using chambers to absorb the impact force of the recoil mass. 
         [0028]    The gas ports defined in the barrel are depicted in the drawings as essentially perpendicular to the linear axis of the barrel. However, embodiments where the direction of the gas ports are angled as compared to this perpendicular arrangement or where a port is beveled can be preferred. Furthermore, the size and shape of any of the gas ports used or depicted is not fixed to the circular or oval ports specifically shown. The size, shape, number of gas ports, and the direction of one of more of the gas ports or tubes can be varied for a number of reasons, including preventing the clogging or spoiling of gas flow. Similarly, gas ports are shown at the lower surface of the interior bore of the barrel in the drawings, but there is no requirement that they be placed exclusively at that position. 
         [0029]    In  FIG. 3   b  the projectile of cartridge, represented as cylinder ( 120 ), has moved through barrel ( 100 ) in response to firing. Gas pressure in barrel ( 100 ) moves through gas port ( 158 ) and through gas manifold ( 154 ) in communication with recoil mass chamber ( 190 ) to force movement in rearward direction ( 210 ) of recoil mass ( 160 ). The counter recoil suppressive force represented by ( 200 ) is generated in reaction to the movement of the recoil mass ( 160 ). The recoil mass and other operating parts can be composed of metal, such as steel or aluminum, or of other or heavier materials such as tungsten or titanium. The weight of the recoil mass ( 160 ) can be varied depending on the size of the cartridge intended. For a 12-gauge shotgun with 28 inch barrel, for example, a recoil mass weight of about 0.5 lbs (about 225 grams) or about 0.4 lbs (about 180 grams) can be used. Of course, various shotgun barrel lengths, such as the general range between 26-30 inches, can be selected. Furthermore, the bolt assembly can be selected from the sizes and weights generally used or available in the field, such as a weight of approximately 0.7 lbs (about 320 grams). As shown in the chart of  FIG. 5  calculated from an exemplary, hypothetical shotgun and operator as discussed here, the suppressive counter-acting force can result in a near instantaneous reduction in recoil at a point near the initial impulse (about 0.0025 secs in  FIG. 5 ), to dramatically reduce the felt recoil forces for a period of time. The total felt recoil force for a calculation as shown in  FIG. 5  is typically represented by the area under the curve, and the operation of the counter-acting recoil mass and the suppressive force it generates reduces that area significantly (see arrow in  FIG. 5 ). 
         [0030]    In  FIG. 3   c  the projectile ( 120 ) has moved past one or more gas port ( 156 ) in manifold ( 154 ) to allow pressurized gas to force movement in rearward direction ( 220 ) of action piston ( 172 ) in tube ( 170 ). Movement of piston ( 172 ) pushes rod ( 180 ) to begin rearward movement of bolt assembly ( 110 ) to release spent cartridge from bolt face ( 114 ). The recoil mass is further along in its movement in the chamber ( 190 ), although the placement of recoil mass ( 160 ) and piston ( 172 ) is estimated in these figures. 
         [0031]    In  FIG. 3   d  the projectile has left the barrel ( 100 ) and recoil mass ( 160 ) is at or near rearward point and/or beginning forward movement pushed by recoil spring or other elastic device (not shown). Piston ( 172 ) generally does not travel the full extent of tube ( 170 ) and here is shown at approximate rearward point to force bolt assembly ( 110 ) back. Gap in area between end of barrel ( 100 ) and bolt face ( 114 ) allows rotating bolt face ( 114 ) and ejector (not shown) to release spent cartridge shell ( 121 ). Direction that spent cartridge is ejected can be controlled by design choices according to devices and technology available in the art. Thus, upward, downward, or left/right directional ejection or the ability to change the direction for left or right handed operators can be used and incorporated into a firearm as discussed here and known in the art. 
         [0032]    After spent cartridge is ejected, return spring moves bolt carriage assembly forward and bolt face ( 114 ) catches next cartridge advancing into a loading position from magazine or feed tube (not shown). In optional embodiments, a lock system is used to prevent the next cartridge from moving into a loading position unless the bolt assembly is in proper placement. After the next cartridge is advanced and moved into position on the bolt face, the bolt assembly continues forward and locks into the firing or loaded position. 
         [0033]      FIG. 4  depicts an exemplary recoil mass system that can be incorporated into a firearm where the elements are as described above. Here, a first gas port ( 158 ) set of ports allows pressurized gas to be in communication with gas manifold ( 154 ) through tubes ( 152 ) also referred to as connector tubes. Gas manifold ( 154 ) can be used to both connect chamber (not shown) to barrel (not shown) and to direct pressurized gas in various directions. Gas flow tubes ( 155 ) internal to gas manifold can regulate the amount of gas that is directed into recoil mass chamber and therefore to control amount of force that acts on recoil mass. An external, operator-controlled regulator can be incorporated into the manifold design to allow the operator to adjust flow of gas into chamber, thereby controlling the counter-acting force generated by movement of recoil mass. This as well as other regulators can therefore be used to bleed some part of the gas pressure out of the system during operation. Use of a regulator can advantageously adjust the firearm for different shotgun cartridges and the impulses different cartridges may generate. 
         [0034]      FIG. 6  shows another side view of an exemplary counter recoil or recoil suppressing device of the invention in a more schematic or idealized presentation. In this view, internal aspects of an exemplary bolt assembly, gas manifold and gas communication system, and recoil mass chamber can be seen. Parts are labeled as in the previous drawings. In  FIG. 6 , the firing pin ( 161 ) can be seen internal to bolt assembly ( 110 ), and external elements of bolt face ( 114 ) are more pronounced. Additional elements ( 163 ) visible in bolt assembly ( 110 ) can link with rod or action piston not shown in this view. Optional side bleed ports ( 164 ) in gas manifold ( 154 ) can be used to reduce gas pressure distributed by manifold, but optional regulator to control external bleed of gas pressure is not depicted. Similar to the operation described above, the flow of pressurized gas from port ( 158 ) through tube ( 152 ) and manifold ( 154 ) allows initial space in chamber ( 190 ) to fill with gas and thereby force movement of recoil mass ( 160 ). Spring ( 192 ) returns recoil mass ( 160 ) to its forward position. Here the spring ( 192 ) is shown to encompass the entire chamber ( 190 ), but other spring arrangements, and indeed other return devices that are not springs, can be selected and used. The size of the initial space at forward end of chamber ( 190 ), here shown in opposite direction of that shown in  FIGS. 3   a - 3   d,  can be selected from various determined sizes for a particular firearm. Here the gap is essentially below the internal gas flow tubes ( 155 ) visible in manifold ( 154 ) and is relatively small. The configuration of the gap area can also be changed from the simple cylinder shown here. The placement and extent of the buffer device ( 162 ) can be seen in this side view. 
         [0035]    The buffer device or shock absorbers incorporated can be one of many available in the art, including elastomer buffers. For example, a piston or rod can penetrate an elastomer buffer to reduce the forces on impact. A flange can be incorporated on the rod or piston to prevent the rod or piston from slipping or form moving beyond a desired point. An elastomer buffer can be made of several ring elements and the control of the forces can accordingly be determined by the selection of the ring elements. For example, if a relatively weak cartridge is fired, the ring elements of elastomer buffer are only partially or slightly compressed. When a strong cartridge is fired, then multiple ring elements of elastomer buffer are compressed. Alternatively, fluidic buffers employing a piston and chambers filled with viscous fluid can be used to temper the forces at impact. Fluidic devices are available in the art and any available device can be selected and used. 
         [0036]    Terms such as “forward”, “rearward”, “under,” “over,” “in front of,” “the back of the gun,” or “behind,” “anterior,” “posterior,” “downward,” “upward,” or “transverse,” are used here as somebody firing a gun would understand and perceive them, which is by reference to the linear or firing axis of the barrel when the gun is held in the usual horizontal attitude. Furthermore, “firearm” as used here encompasses shotguns, rifles, handguns, pistols, heavy caliber guns, sniper rifles, firearms with automatic and semiautomatic action, mountable and portable cannons, firearms or cannons mounted on aircraft or naval vessels, multiple barrel firearms, firearms or cannons mounted on armored personnel carriers or other armored vehicles, and machine guns or cannons mounted on armored or non-armored vehicles or vessels. 
         [0037]    Recoil mass chambers as shown and described here need not be positioned in parallel with the barrel, but can be tilted up or down to further adjust the counter-acting and recoil suppressive forces generated. Similarly, the movement of the recoil mass need not be parallel to the linear axis of the barrel. While not depicted in the drawings, embodiments where the recoil mass moves in a tilted or curved path with respect to the barrel can be employed. 
         [0038]    In any embodiment, the gas manifold or gas connector tubes used can include a pressure equalizing, bleed, or exhaust port or valve in order to reset the pressure in the recoil chamber, and/or action tube, prior to the next firing of the firearm. As noted above, the recoil mass chamber and the action piston tube can themselves include a pressure release valve or gauge or exhaust port, and combinations of exhaust ports or bleed gauges or valves can be used on the one or more manifolds, one of more connector tubes, and/or one or more chambers or tubes. Furthermore, the recoil return device need not be a spring, but can be any elastic or similar device or composition. A buffer or fluidic buffer system known in the art can be used at both ends of the recoil mass chamber if desired, and can also be used at one or both ends of the action piston tube. 
         [0039]    The positioning of the barrel of the weapon relative to the grip or stock of the weapon can effectively allow one to manage part of the recoil moment or force component. Optionally, this invention can incorporate different placement positions of the barrel relative to the height of a grip or the stock, such as at about 5% to about 95% of the height of the grip or stock, or about 40% to about 80%, or about 50% to about 70%, or about 60% to about 70%. As stated herein, any particular configuration of the linear axis of the barrel relative to the grip or stock can be selected. 
         [0040]    In one particular embodiment as shown in  FIGS. 1 ,  2 , and  3   a  for example, the invention comprises a mobile bolt assembly made up of connected parts that comprise a bolt carriage body ( 110 ), a rotating bolt face ( 114 ), and a carriage track or guide. The action piston ( 180 ), which moves in response to gas pressure, pushes the bolt rearward. Shotguns with similar gas-operated systems are known and available to one of skill in the art, and the invention is not limited by the selection of a particular bolt assembly or bolt design or movement. 
         [0041]    As explained for the embodiments of the drawings, however, the rearward movement of the action piston drives the rod assembly rearward causing the rod, or optionally rods located at various points, to drive the bolt housing rearward. The bolt carriage or assembly ( 110 ) can be moved back either by hand through the charging lever ( 116 ) or automatically. The bolt carriage generally travels a straight-line path of motion in the depicted embodiments, but may have other desired paths. Longitudinal grooves or tracks or incorporated rollers in the receiver (not shown) guide the bolt carriage, together with the bolt return spring and action piston. 
         [0042]    Generally, the bolt or bolt assembly cannot be moved alone. The movement distance of the bolt assembly is longer than the length of a cartridge ( 120 + 121 ). The bolt face ( 114 ) can be penetrated by a locking lever or hook (not shown). 
         [0043]    To load and fire the next round, the bolt carriage ( 110 ) returns to the front position, at the end of which the bolt face ( 114 ) contacts the rearward or breech end of the barrel ( 100 ). To lock the bolt or bolt face against the breech, the rotating bolt face can have locking cams or surfaces to engage receiver as it moves forward and rotates. An additional locking element or projection can release a tilting lever to lock the bolt face or bolt carriage from another point along the receiver. The firing pin is in active mode once the bolt is locked in the breech. 
         [0044]    It may be desirable to design the cartridge ejection system for a desired direction, except at the reloading mechanism. For example, if a cartridge gripping device is positioned above the cartridge loading chamber, then the ejection can take place to the right or to the left, or even below, depending on where a cartridge case or spent shell port can be placed. From the foregoing, persons of ordinary skill in the art will appreciate that improved cartridge ejection devices and arrangements have been disclosed and are available. For instance, a stationary ejector can operate with one or two cartridge extractor hooks such that, when the bolt carriage moves rearward, the cartridge or cartridge shell is extracted from the bolt face by extractor hooks moving into contact a position. Then, the base of the cartridge shell strikes the stationary ejector and the shell is ejected. 
         [0045]    One skilled in the art can devise and create numerous other examples according to this invention. Examples may also incorporate additional firearm elements known in the art, including muzzle brake, multiple barrels, blow sensor, barrel temperature probe, electronic firing control, mechanical firing control, electromagnetic firing control, and targeting system, for example. One skilled in the art is familiar with techniques and devices for incorporating the invention into a variety of firearm examples, with or without additional firearm elements know in the art, and designing firearms that take advantage of the improved force distribution and recoil reduction characteristics of the invention.