PATENT ABSTRACT
In one embodiment, a less lethal munition including a ring airfoil projectile. The flight trajectory of the projectile has increased accuracy resulting from the aerodynamic stabilization of the projectile. In some embodiments, the projectile is both aerodynamically stabilized and spin stabilized.

PATENT DESCRIPTION
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a continuation application of U.S. patent application Ser. No. 12/233,483, filed Sep. 18, 2008, entitled LESS LETHAL AMMUNITION, which claims the benefit of priority to U.S. Provisional Patent Application Ser. No. 60/994,336 filed Sep. 18, 2007, entitled RING AIRFOIL GLIDER AMMUNITION LESS LETHAL, both of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention pertains to ammunition, and in particular to less-lethal munitions incorporating sub-caliber projectiles. 
       SUMMARY OF THE INVENTION 
       [0003]    One aspect of the present invention pertains to embodiments including a sabot for pushing a projectile such that the projectile exits the muzzle of the gun with the sabot being retained within the barrel. 
         [0004]    Yet another aspect of the present invention pertains to a multi-piece sabot, in which a portion of the sabot pushes a projectile, and a portion of the sabot (either the same portion or a different portion) is ejected from the muzzle of the gun barrel. 
         [0005]    Yet another aspect of some embodiments of the present invention pertain to methods and apparatus for linking together multiple munitions for semi-automatic or automatic firing of the munitions. 
         [0006]    It will be appreciated that the various apparatus and methods described in this summary section, as well as elsewhere in this application, can be expressed as a large number of different combinations and subcombinations. All such useful, novel, and inventive combinations and subcombinations are contemplated herein, it being recognized that the explicit expression of each of these myriad combinations is excessive and unnecessary. 
         [0007]    These and other aspects and features of various embodiments will be shown in the drawings, claims, and text that follows. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1   a  is a cross sectional elevated view of ammunition according to one embodiment of the present invention. 
           [0009]      FIG. 1   b  is an exploded cross sectional view of the ammunition of  FIG. 1   a.    
           [0010]      FIG. 2  illustrates a cross sectional view of the round of  FIG. 1   a , feeding into chamber of a gun. 
           [0011]      FIG. 3  illustrates a cross sectional view of the round of  FIG. 1   a  chambered at the firing point in a gun barrel. 
           [0012]      FIG. 4  illustrates a cross sectional view of the round of  FIG. 1   a  as the round telescopes and fires the projectile. 
           [0013]      FIG. 5  illustrates a cross sectional view of the round of  FIG. 1   a  as the projectile is launched in the barrel chamber. 
           [0014]      FIG. 6  illustrates a cross sectional view of the round of  FIG. 1   a  as the projectile is released to travel down the gun bore and the round begins to eject. 
           [0015]      FIG. 7  illustrates a cross sectional view of the assembled ammunition round as the projectile, and F.O.D. and sabot exits the muzzle. 
           [0016]      FIG. 8  illustrates a cross sectional view of a ring airfoil projectile according to one embodiment of the present invention. 
           [0017]      FIG. 9  illustrates an elevated cross sectional view of ammunition according to another embodiment of the present invention.  FIG. 10  illustrates an elevated cross sectional view of a round according to another embodiment of the present invention. 
           [0018]      FIG. 10  is an elevated cross sectional view of a round according to another embodiment of the present invention. 
           [0019]      FIG. 11  is an elevated cross sectional view of a round according to another embodiment of the present invention. 
           [0020]      FIG. 12  is an elevated cross sectional view of a round according to another embodiment of the present invention. 
           [0021]      FIG. 13   a  is an elevated cross sectional view of a round according to another embodiment of the present invention. 
           [0022]      FIG. 13   b  is a cross sectional representation of the sabots of  FIG. 13   a  after separation. 
           [0023]      FIG. 13   c  is a perspective photographic representation of the linkage assembly for the round of  FIG. 13   a.    
           [0024]      FIG. 14  is an elevated cross sectional view of a round according to another embodiment of the present invention. 
           [0025]      FIG. 15  is an elevated cross sectional view of a round according to another embodiment of the present invention. 
           [0026]      FIG. 16   a  is an elevated cross sectional view of a munition according to another embodiment of the present invention. 
           [0027]      FIG. 16   b  is a side perspective photographic view of the apparatus of  FIG. 16   a , except without the linkage. 
           [0028]      FIG. 16   c  is a perspective photographic representation of a portion of the apparatus of  FIG. 16   b.    
           [0029]      FIG. 16   d  is a perspective photographic representation of a portion of the apparatus of  FIG. 16   b.    
           [0030]      FIG. 16   e  is a perspective photographic representation of a portion of the apparatus of  FIG. 16   b.    
           [0031]      FIG. 16   f  is a perspective photographic representation of a portion of the apparatus of  FIG. 16   b.    
           [0032]      FIG. 16   g  is a perspective photographic representation of a portion of the apparatus of  FIG. 16   b , with the linkage mounted. 
           [0033]      FIG. 16   h  is a perspective photographic representation of a portion of the apparatus of  FIG. 16   b , with the linkage mounted. 
           [0034]      FIG. 17  illustrates a cross sectional view of the round of  FIG. 16   a  feeding into a chamber of a gun. 
           [0035]      FIG. 18  illustrates a cross sectional view of the round of  FIG. 16   a  chambered at the firing point in a gun barrel. 
           [0036]      FIG. 19  illustrates a cross sectional view of the round of  FIG. 16   a  as the round telescopes and fires the projectile. 
           [0037]      FIG. 20  illustrates a cross sectional view of the round of  FIG. 16   a  as the projectile is launched in the barrel chamber and the sabot is stopped. 
           [0038]      FIG. 21  illustrates a cross sectional view of the round of  FIG. 16   a  as the projectile and petals are released to travel down the gun bore and the round begins to eject. 
           [0039]      FIG. 22  is a partial cross sectional view of the munition of  FIG. 16   a  being automatically loaded into a gun. 
           [0040]      FIG. 23  is a partial cross sectional view of the munition of  FIG. 16   a  being automatically loaded into a gun. 
           [0041]      FIG. 24  is a partial cross sectional view of the munition of  FIG. 16   a  being automatically loaded into a gun. 
           [0042]      FIG. 25  is a partial cross sectional view of the munition of  FIG. 16   a  being automatically loaded into a gun. 
           [0043]      FIG. 26  is a partial cross sectional view of the munition of  FIG. 16   a  being automatically loaded into a gun. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0044]    For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. 
         [0045]    The use of an N-series prefix for an element number (NXX.XX) refers to an element that is the same as the non-prefixed element (XX.XX), except as shown and described thereafter. As an example, an element  1020 . 1  would be the same as element  20 . 1 , except for those different features of element  1020 . 1  shown and described. Further, common elements and common features of related elements are drawn in the same manner in different figures, and/or use the same symbology in different figures. As such, it is not necessary to describe the features of  1020 . 1  and  20 . 1  that are the same, since these common features are apparent to a person of ordinary skill in the related field of technology. Although various specific quantities (spatial dimensions, temperatures, pressures, times, force, resistance, current, voltage, concentrations, etc.) may be stated herein, such specific quantities are presented as examples only, and are not to be construed as limiting. 
         [0046]    Incorporated herein by reference are U.S. patent application Ser. Nos. 12/045,647, filed Mar. 10, 2008, attorney docket no. 19337-81338; and 12/181,190, filed Jul. 28, 2008, attorney docket no. 19337-83244. 
         [0047]      FIGS. 1   a  and  1   b  show cross-sectional and exploded views of a munition  20  according one embodiment of the present invention. Ammunition  20  includes a payload section  60  supported by a launch support assembly  40 . Further, a telescoping assembly  30  co-acts with launch assembly  40  to provide a breech block resetting capability for automatic weapons. Ammunition  20  can be fired from any type of gun, including the Mk 19 machine gun, the Mk M203 and Milkor single shot weapons, as well as 37 mm guns. 
         [0048]    Telescoping assembly  30  includes a support member  32  that is slidingly received within a pocket of launch support member  42 . Telescoping support further includes a pocket  32 . 3  that receives within it an explosive assembly  34 . In one embodiment, explosive assembly  34  includes an initiator  34 . 1  in fluid communication via a passageway  34 . 3  within packing  34 . 2  to an explosive charge  34 . 4 . A resilient seal  36  provides sealing of the exploded charge  34 . 4  between members  32  and  34  prior to the rearward telescoping of member  32  relative to member  34 . Circumferential abutment  32 . 4  interacts with abutment  42 . 4  to limit the sliding of member  32  relative to member  42 . In some embodiments, telescoping assembly  30  further includes a ball-shaped firing pin  37  that is launched into and thereby causes ignition of initiator  44 . 1  during firing of ammunition  20 . Telescoping assembly  30  is preferably present in those versions of ammunition  20  that are fired from automatic weapons. Some embodiments of the present invention pertain to single shot weapons that do not need the function provided by telescoping assembly  30 . 
         [0049]    Launch support assembly  40  provides secure mechanical coupling to the firing chamber of a gun, supports payload section  60 , slidingly couples to assembly  30  as previously described, and further supports a linkage assembly  24 . Linkage assembly  24 , as shown in  FIGS. 1   a  and  1   b , is a sliding link assembly that couples adjacent ammunitions  20  to each other. Linkage assembly includes a seal and retaining member  24 . 1  that is received on the outer diameter  42 . 11  of support  42 . A link mount  24 . 2  is slidingly received over the outer diameter of retainer  24 . 1 . A first Link  24 . 3  is tightly secured to the outer diameter of link mount  24 . 2 , and further receives and retains a captured coupling link  24 . 4  that couples to another coupling link of an adjacent ammunition  20 . Operation of the links, as well as operation of a munition, will be shown in  FIGS. 29-34  that follow. 
         [0050]    Support member  42  of Launch support assembly  40  further includes within it a pocket  42 . 3  that receives an explosive assembly  44 . Explosive assembly includes an initiator  44 . 1  that is in fluid communication with an explosive charge  44 . 4  by way of a central passage  44 . 3  within packing material  44 . 2 . 
         [0051]    Explosive charge  44 . 4  is placed within a combustion chamber  42 . 1  of support  42 . A plurality of gas release passages  42 . 5  provide fluid communication of the combusted explosive charge with a plurality of hemispherical balls at the exit of the passage. 
         [0052]    In some embodiments, one or both of the combustion chambers  32 . 1  or  42 . 1  can include a rupture diaphragm such as a copper disc that is conformally placed between the explosive charge and the chamber defined by corresponding member  32  or  42 . This disc contains the explosive gases until they reach sufficient pressure to rupture the disc wall and subsequently release the combusted gases into the corresponding gas passages  32 . 5  or  42 . 5 . 
         [0053]    Extending from one end of support  42  is a rod  42 . 7  that includes a receptacle for a fastener, such as threaded receptacle  42 . 9 . Support  42  further includes a circumferentially extending shoulder  42 . 6  located proximate to the end of gas release passages  42 . 5 . A pocket is formed around the base of rod  42 . 7  between the outer diameter  42 . 8  of the rod and the inside of shoulder  42 . 6 . 
         [0054]    A payload section  60  is received on rod  42 . 7  and shoulder  42 . 6  of support member  42 . Payload section  60  includes a sabot that is fittingly received on shoulder  42 . 6 . A frangible retainer  64  is received on the distal end of rod  42 . 7 . A ringed airfoil projectile  80  is captured between sabot  62  and retainer  64 . 
         [0055]    Sabot  62  includes a curving annular middle section located between an inner cylindrical portion  62 . 2  and an outer cylindrical portion  62 . 1 . The inner face of the annular midsection is received against shoulder  42 . 6 . The inner diameter of cylindrical section  62 . 2  is in sliding contact with outer diameter  42 . 8  of rod  42 . 7 . The outer diameter of outer cylindrical portion  62 . 1  includes an outer most diameter that is in sliding contact with the inner diameter and rifling  22 . 2  of the barrel  22 . 1  of a gun  22 , as will be shown and described for  FIGS. 29-34 . Sabot  62  further includes a plurality of circumferentially extending drive features  62 . 4  that couple to corresponding and complementary driven features of ring airfoil  80 . 
         [0056]    Retainer  64  includes a center support ring  64 . 2  that is held on the end of rod  42 . 7  by a fastener or other coupling means  46 . A plurality of outwardly extending and separated petals  64 . 1  extend from support ring  64 . 2  a frangible feature such as a notch is preferably located at the connection of a petal to the support ring, and acts as a stress riser during operation. Each petal extends outwardly and aft (aft being defined as the direction toward telescoping assembly  30  and forward being defined as the direction toward payload section  60  and further toward the open end of the gun barrel), and on the aft face of each petal there is a small pocket for receiving within it the leading edge  90  of ring air foil  80 . Ring air foil  80  is captured on ammunition  20  between sabot  62  and retainer  64 . 
         [0057]      FIG. 8  shows cross sectional, side elevational view of ring airfoil  80 . Airfoil  80  comprises a substantially hollow, annular ring wall. The wall of airfoil  80  has an airfoil section  94  that includes a cambered outer surface  82  and cambered inner surface  84 . These inner and outer surfaces  82  and  84 , respectively, meet at a substantially blunt leading edge  90 , and at a substantially tapered trailing edge  92 . The inner surface  84  of airfoil  80  defines a substantially open central aperture  86 . Preferably, ring airfoil  80  is a body of revolution formed by rotating airfoil section  94  about central axis  86 . 1 . Ring airfoil  80  has a length  86 . 2  from leading edge  90  to trailing edge  92 , and an outer diameter  82 . 1  extending across the outermost portion of outer surface  82 , and an innermost diameter or throat  86 . 4  extending across the innermost portion of inner surface  84 . In some embodiments, trailing edge  92  includes a plurality of drive features (such as rectangular cutouts) that mate with complementary features on sabot  62 . 
         [0058]    Tables 1 and 2 present data for outer diameter and inner diameter, respectively, related to a programming table of values for a computer numerically controlled machine to fabricate a projectile according to one embodiment of the present invention. In both of these tables, the first column represents the diametrical distance (or twice the radius from the center line), and the second column represents a location along the Z Axis. A representative projectile can be machined from this data. If a cutting tool having a radius of about 0.016 is positioned in accordance with this data, it will have a tangent point of contact on the airfoil surface. In one embodiment, the overall length of the projectile is about 1 inch. 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Diametral Distance 
                 Axial Location 
               
               
                   
                   
               
             
             
               
                   
                 1.4364 
                 +.0158 
               
               
                   
                 1.4422 
                 +.0153 
               
               
                   
                 1.4476 
                 +.0148 
               
               
                   
                 1.4530 
                 +.0140 
               
               
                   
                 1.4586 
                 +.0131 
               
               
                   
                 1.4644 
                 +.0119 
               
               
                   
                 1.4708 
                 +.0104 
               
               
                   
                 1.4774 
                 +.0088 
               
               
                   
                 1.4842 
                 +.0066 
               
               
                   
                 1.4908 
                 +.0045 
               
               
                   
                 1.4968 
                 +.0022 
               
               
                   
                 1.5032 
                 −.0004 
               
               
                   
                 1.5086 
                 −.0029 
               
               
                   
                 1.5136 
                 −.0055 
               
               
                   
                 1.5188 
                 −.0064 
               
               
                   
                 1.5236 
                 −.0113 
               
               
                   
                 1.5280 
                 −.0145 
               
               
                   
                 1.5324 
                 −.0179 
               
               
                   
                 1.5366 
                 −.0215 
               
               
                   
                 1.5410 
                 −.0255 
               
               
                   
                 1.5452 
                 −.0298 
               
               
                   
                 1.5492 
                 −.0344 
               
               
                   
                 1.5532 
                 −.0393 
               
               
                   
                 1.5572 
                 −.0445 
               
               
                   
                 1.5812 
                 −.0502 
               
               
                   
                 1.5850 
                 −.0582 
               
               
                   
                 1.5888 
                 −.0627 
               
               
                   
                 1.5726 
                 −.0697 
               
               
                   
                 1.5762 
                 −.0771 
               
               
                   
                 1.5798 
                 −.0850 
               
               
                   
                 1.5834 
                 −.0934 
               
               
                   
                 1.5868 
                 −.1024 
               
               
                   
                 1.5902 
                 −.1125 
               
               
                   
                 1.5936 
                 −.1230 
               
               
                   
                 1.5968 
                 −.1340 
               
               
                   
                 1.5996 
                 −.1457 
               
               
                   
                 1.6028 
                 −.1582 
               
               
                   
                 1.6056 
                 −.1713 
               
               
                   
                 1.6064 
                 −.1755 
               
               
                   
                 1.6090 
                 −.1898 
               
               
                   
                 1.6116 
                 −.2048 
               
               
                   
                 1.6138 
                 −.2207 
               
               
                   
                 1.6180 
                 −.2375 
               
               
                   
                 1.6176 
                 −.2519 
               
               
                   
                 1.6194 
                 −.2705 
               
               
                   
                 1.6210 
                 −.2901 
               
               
                   
                 1.6222 
                 −.3109 
               
               
                   
                 1.6234 
                 −.3329 
               
               
                   
                 1.6238 
                 −.3420 
               
               
                   
                 1.6246 
                 −.3888 
               
               
                   
                 1.6252 
                 −.3907 
               
               
                   
                 1.6252 
                 −.4127 
               
               
                   
                 1.6252 
                 −.4346 
               
               
                   
                 1.6246 
                 −.4523 
               
               
                   
                 1.6240 
                 −.4888 
               
               
                   
                 1.6228 
                 −.4854 
               
               
                   
                 1.6218 
                 −.4987 
               
               
                   
                 1.6200 
                 −.5181 
               
               
                   
                 1.6178 
                 −.5373 
               
               
                   
                 1.6156 
                 −.5558 
               
               
                   
                 1.6134 
                 −.5715 
               
               
                   
                 1.6108 
                 −.5886 
               
               
                   
                 1.6076 
                 −.6057 
               
               
                   
                 1.6042 
                 −.6229 
               
               
                   
                 1.5998 
                 −.6434 
               
               
                   
                 1.5956 
                 −.6612 
               
               
                   
                 1.5912 
                 −.6789 
               
               
                   
                 1.5912 
                 −.6789 
               
               
                   
                 1.5864 
                 −.6985 
               
               
                   
                 1.5812 
                 −.7143 
               
               
                   
                 1.5758 
                 −.7315 
               
               
                   
                 1.5704 
                 −.7484 
               
               
                   
                 1.5644 
                 −.7652 
               
               
                   
                 1.5574 
                 −.7843 
               
               
                   
                 1.5508 
                 −.8010 
               
               
                   
                 1.5440 
                 −.8180 
               
               
                   
                 1.5366 
                 −.8363 
               
               
                   
                 1.5288 
                 −.8532 
               
               
                   
                 1.5210 
                 −.8694 
               
               
                   
                 1.5138 
                 −.8847 
               
               
                   
                 1.5080 
                 −.8995 
               
               
                   
                 1.4982 
                 −.9143 
               
               
                   
                 1.4944 
                 −.9213 
               
               
                   
                 1.4882 
                 −.9362 
               
               
                   
                 1.4782 
                 −.9534 
               
               
                   
                 1.4648 
                 −.9724 
               
               
                   
                 1.4554 
                 −.9881 
               
               
                   
                 1.4463 
                 −.1.0028 
               
               
                   
                   
                 (off surface for reference of 
               
               
                   
                   
                 shape only +1   −.0)   
               
               
                   
                 1.4394 
                 −.1.10136 
               
               
                   
                   
                 (off surface for reference of 
               
               
                   
                   
                 shape only) 
               
               
                   
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 Diametral Distance 
                 Axial Location 
               
               
                   
                   
               
             
             
               
                   
                 1.4284 
                 +.0158 
               
               
                   
                 1.4148 
                 +.0146 
               
               
                   
                 1.3994 
                 +.0125 
               
               
                   
                 1.3842 
                 +.0091 
               
               
                   
                 1.3710 
                 +.0051 
               
               
                   
                 1.3688 
                 +.0002 
               
               
                   
                 1.3470 
                 −.0054 
               
               
                   
                 1.3416 
                 −.0083 
               
               
                   
                 1.3294 
                 −.0157 
               
               
                   
                 1.3156 
                 −.0253 
               
               
                   
                 1.3054 
                 −.0332 
               
               
                   
                 1.2932 
                 −.0437 
               
               
                   
                 1.2878 
                 −.0492 
               
               
                   
                 1.2708 
                 −.0868 
               
               
                   
                 1.2544 
                 −.0859 
               
               
                   
                 1.2392 
                 −.1054 
               
               
                   
                 1.2282 
                 −.1254 
               
               
                   
                 1.2142 
                 −.1458 
               
               
                   
                 1.2036 
                 −.1668 
               
               
                   
                 1.1946 
                 −.1878 
               
               
                   
                 1.1888 
                 −.2100 
               
               
                   
                 1.1808 
                 −.2323 
               
               
                   
                 1.1754 
                 −.2544 
               
               
                   
                 1.1710 
                 −.2780 
               
               
                   
                 1.1672 
                 −.2971 
               
               
                   
                 1.1640 
                 −.3178 
               
               
                   
                 1.1616 
                 −.3381 
               
               
                   
                 1.1588 
                 −.3771 
               
               
                   
                 1.1584 
                 −.3961 
               
               
                   
                 1.1588 
                 −.4155 
               
               
                   
                 1.1602 
                 −.4382 
               
               
                   
                 1.1622 
                 −.4583 
               
               
                   
                 1.1650 
                 −.4817 
               
               
                   
                 1.1688 
                 −.5085 
               
               
                   
                 1.1734 
                 −.5326 
               
               
                   
                 1.1788 
                 −.5601 
               
               
                   
                 1.1848 
                 −.5890 
               
               
                   
                 1.1918 
                 −.6182 
               
               
                   
                 1.1994 
                 −.6468 
               
               
                   
                 1.2076 
                 −.6747 
               
               
                   
                 1.2182 
                 −.7020 
               
               
                   
                 1.2258 
                 −.7285 
               
               
                   
                 1.2358 
                 −.7544 
               
               
                   
                 1.2464 
                 −.7796 
               
               
                   
                 1.2578 
                 −.8041 
               
               
                   
                 1.2698 
                 −.8284 
               
               
                   
                 1.2828 
                 −.8885 
               
               
                   
                 1.2988 
                 −.8776 
               
               
                   
                 1.3118 
                 −.9025 
               
               
                   
                 1.3278 
                 −.9277 
               
               
                   
                 1.3446 
                 −.9530 
               
               
                   
                 1.3824 
                 −.9788 
               
               
                   
                 1.3812 
               
               
                   
                   
               
             
          
         
       
     
         [0059]    Tables 3 and 4 present data for outer diameter and inner diameter, respectively, related to a programming table of values for a computer numerically controlled machine to fabricate a projectile according to another embodiment of the present invention. In both of these tables, the first column represents the diametrical distance (or twice the radius from the center line), and the second column represents a location along the Z Axis. A representative projectile can be machined from this data. If a cutting tool having a radius of about 0.016 is positioned in accordance with this data, it will have a tangent point of contact on the airfoil surface. In one embodiment, the overall length of the projectile is about 1 inch. 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 3 
               
               
                   
                   
               
               
                   
                 Diametral Distance 
                 Axial Location 
               
               
                   
                   
               
             
             
               
                   
                 1.4364 
                 +.0156 
               
               
                   
                 1.4422 
                 +.0153 
               
               
                   
                 1.4476 
                 +.0148 
               
               
                   
                 1.4530 
                 +.0140 
               
               
                   
                 1.4586 
                 +0131 
               
               
                   
                 1.466 
                 +0.119 
               
               
                   
                 1.4708 
                 +.0104 
               
               
                   
                 1.4774 
                 +.0086 
               
               
                   
                 1.4842 
                 +.0066 
               
               
                   
                 1.4908 
                 +.0045 
               
               
                   
                 1.4968 
                 +.0022 
               
               
                   
                 1.5032 
                 −.0004 
               
               
                   
                 1.5086 
                 −.0029 
               
               
                   
                 1.5138 
                 −.0055 
               
               
                   
                 1.5188 
                 −.0084 
               
               
                   
                 1.5236 
                 −.0113 
               
               
                   
                 1.5280 
                 −.0145 
               
               
                   
                 1.5324 
                 −.0179 
               
               
                   
                 1.5366 
                 −.0215 
               
               
                   
                 1.5410 
                 −0.255 
               
               
                   
                 1.5452 
                 −.0298 
               
               
                   
                 1.5492 
                 −.0344 
               
               
                   
                 1.5532 
                 −.0393 
               
               
                   
                 1.5572 
                 −.0445 
               
               
                   
                 1.5612 
                 −.0502 
               
               
                   
                 1.5650 
                 −.0682 
               
               
                   
                 1.5688 
                 −.0627 
               
               
                   
                 1.5726 
                 −.0697 
               
               
                   
                 1.5762 
                 −.0771 
               
               
                   
                 1.5798 
                 −.0850 
               
               
                   
                 1.5834 
                 −.0934 
               
               
                   
                 1.5868 
                 −.1024 
               
               
                   
                 1.5902 
                 −.1125 
               
               
                   
                 1.5936 
                 −.1230 
               
               
                   
                 1.5968 
                 −.1340 
               
               
                   
                 1.5998 
                 −.1457 
               
               
                   
                 1.6028 
                 −.1582 
               
               
                   
                 1.6056 
                 −.1713 
               
               
                   
                 1.6064 
                 −.1755 
               
               
                   
                 1.6090 
                 −.1898 
               
               
                   
                 1.6116 
                 −.2048 
               
               
                   
                 1.6138 
                 −.2207 
               
               
                   
                 1.6160 
                 −.2375 
               
               
                   
                 1.6176 
                 −.2519 
               
               
                   
                 1.6194 
                 −.2705 
               
               
                   
                 1.6210 
                 −.2901 
               
               
                   
                 1.6222 
                 −.3109 
               
               
                   
                 1.6234 
                 −.3329 
               
               
                   
                 1.6238 
                 −.3420 
               
               
                   
                 1.6246 
                 −.3666 
               
               
                   
                 1.6252 
                 −.3907 
               
               
                   
                 1.6252 
                 −.4127 
               
               
                   
                 1.6252 
                 −.4346 
               
               
                   
                 1.6246 
                 −.4523 
               
               
                   
                 1.6240 
                 −.4888 
               
               
                   
                 1.6228 
                 −.4854 
               
               
                   
                 1.6218 
                 −.4987 
               
               
                   
                 1.6200 
                 −.5181 
               
               
                   
                 1.6178 
                 −.5373 
               
               
                   
                 1.6156 
                 −.5556 
               
               
                   
                 1.6134 
                 −.5715 
               
               
                   
                 1.6106 
                 −.5886 
               
               
                   
                 1.6076 
                 −.6057 
               
               
                   
                 1.6042 
                 −.6229 
               
               
                   
                 1.5998 
                 −.6434 
               
               
                   
                 1.5956 
                 −.6612 
               
               
                   
                 1.5912 
                 −.6789 
               
               
                   
                 1.5864 
                 −.6965 
               
               
                   
                 1.5812 
                 −.7143 
               
               
                   
                 1.5758 
                 −.7315 
               
               
                   
                 1.5704 
                 −.7484 
               
               
                   
                 1.5644 
                 −.7652 
               
               
                   
                 1.5574 
                 −.7843 
               
               
                   
                 1.5508 
                 −.8010 
               
               
                   
                 1.5440 
                 −.8180 
               
               
                   
                 1.5366 
                 −.8353 
               
               
                   
                 1.5286 
                 −.8532 
               
               
                   
                 1.5210 
                 −.8694 
               
               
                   
                 1.5136 
                 −.8847 
               
               
                   
                 1.5060 
                 −.8995 
               
               
                   
                 1.4982 
                 −.9143 
               
               
                   
                 1.4944 
                 −.9213 
               
               
                   
                 1.4862 
                 −.9362 
               
               
                   
                 1.4762 
                 −.9534 
               
               
                   
                 1.4648 
                 −.9724 
               
               
                   
                 1.4554 
                 −.9881 
               
               
                   
                 1.4463 
                 −.1.0028 
               
               
                   
                 1.4394 
                 −.1.0136 
               
               
                   
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 4 
               
               
                   
                   
               
               
                   
                 Diametral Distance 
                 Axial Location 
               
               
                   
                   
               
             
             
               
                   
                 1.3918 
                 +.0156 
               
               
                   
                 1.3782 
                 +.0146 
               
               
                   
                 1.3628 
                 +.0125 
               
               
                   
                 1.3476 
                 +.0091 
               
               
                   
                 1.3344 
                 +.0051 
               
               
                   
                 1.3220 
                 +.0002 
               
               
                   
                 1.3104 
                 −.0054 
               
               
                   
                 1.3050 
                 −.0083 
               
               
                   
                 1.2928 
                 −.0157 
               
               
                   
                 1.2790 
                 −.0253 
               
               
                   
                 1.2688 
                 −.0332 
               
               
                   
                 1.2566 
                 −.0437 
               
               
                   
                 1.2510 
                 −.0492 
               
               
                   
                 1.2340 
                 −.0668 
               
               
                   
                 1.2178 
                 −.0859 
               
               
                   
                 1.2026 
                 −.1054 
               
               
                   
                 1.1896 
                 −.1254 
               
               
                   
                 1.1776 
                 −.1458 
               
               
                   
                 1.1580 
                 −.1878 
               
               
                   
                 1.1502 
                 −.2100 
               
               
                   
                 1.1440 
                 −.2323 
               
               
                   
                 1.1388 
                 −.2544 
               
               
                   
                 1.1344 
                 −.2760 
               
               
                   
                 1.1306 
                 −2971 
               
               
                   
                 1.1274 
                 −.3178 
               
               
                   
                 1.1250 
                 −.3381 
               
               
                   
                 1.1222 
                 −.3771 
               
               
                   
                 1.1218 
                 −.3961 
               
               
                   
                 1.1222 
                 −.4155 
               
               
                   
                 1.1236 
                 −.4362 
               
               
                   
                 1.1256 
                 −.4583 
               
               
                   
                 1.1284 
                 −.4817 
               
               
                   
                 1.1322 
                 −.5065 
               
               
                   
                 1.1368 
                 −.5326 
               
               
                   
                 1.1422 
                 −.5601 
               
               
                   
                 1.1482 
                 −.5890 
               
               
                   
                 1.1552 
                 −.6182 
               
               
                   
                 1.1628 
                 −.6468 
               
               
                   
                 1.1710 
                 −.6747 
               
               
                   
                 1.1796 
                 −.7020 
               
               
                   
                 1.1890 
                 −.7285 
               
               
                   
                 1.1990 
                 −.7544 
               
               
                   
                 1.2098 
                 −.7796 
               
               
                   
                 1.2210 
                 −.8041 
               
               
                   
                 1.2330 
                 −.8284 
               
               
                   
                 1.2462 
                 −.8685 
               
               
                   
                 1.2602 
                 −.8776 
               
               
                   
                 1.2752 
                 −.9025 
               
               
                   
                 1.2910 
                 −.9277 
               
               
                   
                 1.3080 
                 −.9530 
               
               
                   
                 1.3258 
                 −.9786 
               
               
                   
                 1.3446 
                 −1.007 
               
               
                   
                   
               
             
          
         
       
     
         [0060]    The following is a description of the firing of ammunition as shown in  FIGS. 2-7 . 
         [0061]    Upon being on the bolt face in the ready battery position, latched and ready to be fired, the trigger is pulled. 
         [0062]    The bolt travels forward until the firing pin  22 . 4  is released, about 1″ from the breech face  22 . 3 . 
         [0063]    The pin strikes the aft telescoping charges primer initiating the propellant; simultaneously an initiation ball  37  is propelled forward to a primer  34 . 1  for the forward payload propelling charge, and the expanding gas reacts against the telescoping piston to open the action and auto load function the gun. 
         [0064]    The forward payload propelling charge expands against the sabot/pusher  62  pushing it forward while fracturing the projectile retainer  64  along one or more separation groove(s) on the central hub of the retainer releasing the sabot and projectile assembly for forward travel. 
         [0065]    The sealing and rotating outer diameter  62 . 1  of sabot  62  seals the propelling gas from the action at the forcing cone of the chamber. The sabot/projectile assembly  160  is pushed along the bore and along the center guide mandrill  42 . 7 , throughout the launch sequence. 
         [0066]    The sabot/projectile assembly travels down the bore to the end of the guide mandrill having spin imparted to the assembly by the action of rifling  22 . 2  in the gun bore  22 . 1  rotating the sabot  62  which transfers the rotation by the action of drive dogs  62 . 4  on its forward face engaging slots  88  in the tail  92  of the ring airfoil projectile  80 . 
         [0067]    As the sabot leaves the mandrill the propelling gas are vented down the center of the sabot d own the bore ahead of the sabot/projectile assembly, protecting the ring airfoil projectile from disturbance by the gas, at which point the maximum velocity is achieved for both the sabot and projectile. 
         [0068]    The sabot immediately begins to decelerate due to friction with the bore. This causes the projectile to separate, as it has little or no contact with the bore and little friction retarding its passage down the bore. 
         [0069]    The projectile rides a turbulent boundary layer of air between its outer diameter and the bore guiding and centering it until it exits the muzzle. The sabot exits the muzzle at greatly reduced energy. The ring airfoil  80  is free to fly towards the target. 
         [0070]    As the ring airfoil  80  travels through the air, if it is thought that a higher pressure is created in the duct  86  through it by the comparatively more cambered shaped of the airfoil surface on the inside of the duct in contrast to the lesser curved shape on the periphery of the ring airfoil creating a lower static pressure on the ring airfoil outer surface  82 . This increased drag helps stabilize the projectile along with the gyroscopic spin imparted to it by action of the rifling, allowing the projectile to be less prone to curved flight paths and external disruptions such as cross wind and air disturbances. The center of pressure along the projectile longitudinal axis is aft or coincides with the center of mass. The action of the increased drag in the duct creates an aerodynamic stabilizing force on the projectile as if it has a tail much like an arrow, reducing the dependence on spin stabilization. 
         [0071]      FIG. 9  illustrates a cross sectional view of an assembled ammunition round  120  having a forward hook for retaining the link mount  124  on the mandrill body  142  which is held in place on a shear shoulder  149 . 1  on a chamber seal  149 . Round  120  includes a chamber seal  149  that is attached to support member  142 . Preferably, seal  149  is fabricated from a plastic (such as ABS or aluminum) and is attached to body  142  with an interference fit. Chamber seal  149  includes an outwardly projecting sealing surface that forms a seal with the inner diameter barrel  22 . 1  so as to substantially obstruct the leakage of gas provided by gas release passages  142 . 5 . 
         [0072]    In some embodiments, munition  120  includes a crimped opening  148 . 2  that serves to frictionally couple together supports  132  and  142 . Preferably, there are a plurality of discrete inward crimps  148 . 2  around the periphery of the aft end of body  142 . These crimps capture support  142  within the large inner pocket of member  142 , and prevent inadvertent telescoping of member  132  relative to member  142  during handling. 
         [0073]    During firing, shoulder  149 . 1  of seal  149  is shorn when the bolt comes forward, forcing the link mount shoulder against the chamfer on the barrel breech. The shoulder on the link mount is milled flat to create clearance in the feed tray of the machine gun to prevent rubbing of the shoulder on the feed guide slots. 
         [0074]      FIG. 10  illustrates a cross sectional view of an assembled ammunition round  220  in accordance with another embodiment. Round  220  includes a launch support assembly  240  that is threadingly engaged along interface  241 . 8  to a base  248 . Assembly  240  includes a support  242  that includes at least a portion of a combustion chamber  242 . 1 . Chamber  242 . 1  is generally shaped conically inward, and includes a plurality of gas passageways  242 . 5  that extend outwardly and into fluid communication with the underside of sabot  262 . 
         [0075]    In some embodiments, launch assembly  240  is fabricated, assembled, shipped, and stored as a subassembly. During final assembly of round  220 , an explosive charge  244  is placed in combustion chamber  242 . 1 . A mating base  248  is prepared as a subassembly including a chamber seal  249 , primer holding  244 . 2 , and primer  244 . 1 . Subassemblies  240  and  248  are threadingly engaged to form a finished munition  220 . 
         [0076]    Round  220  is adapted and configured for use in standard single shot launchers like the M203. The forward mandrill  242  can be affixed with a fixed cartridge rim  248  used in place of the telescoping components. Threaded interface  248 . 1  includes male and female threads that can be reversed on the components to be attached if desired. 
         [0077]    The embodiment shown in  FIG. 11  illustrates a cross sectional view of an assembled ammunition round  320  as another embodiment, Round  320  includes a launch support assembly  340  that is substantially the same as assembly  240 . However, round  320  includes a base assembly  348  adapted and configured for use in semi-automatic and automatic guns. Base  348  includes male threads for threadably coupling to the female threads of assembly  340  at threaded interface  348 . 1 . 
         [0078]    Base  348 , when fully assembled, further includes a chamber seal  349  and packing  344 . 2  located within a central pocket. The assembled base  348  further includes an initiator  344 . 1  that provides ignition through central passage  344 . 3  to explosive charge  344 . 4  after being impacted by ball  337 . Ball  337  is retained within a pocket of support assembly  332 . A cover plate  350  is adhered to a face of support  332  to retain ball  337  in its pocket. In one embodiment, cover plate  350  comprises an aluminum diaphragm of about 0.006 inches thickness. 
         [0079]      FIG. 11  includes a linkage assembly  324  and linkage interfaces that are different than those described for round  20 . Referring to  FIG. 11 , and also to  FIGS. 13   c ,  16   a ,  16   b ,  16   g , and  16   h , which have related linkage features, body (or base)  348  includes a region  326 . 1  of reduced outer diameter immediately in front of a region  326  of increased outer diameter. Behind ridge  326  is an area  326 . 2  of constant diameter that is preferably about midway between diameters  326 . 1  and  326 . Preferably, diameter  326 . 2  is about the same as diameter  342 . 15  of support  342 . 
         [0080]    Linkage assembly  324  is preferably spring loaded in tension around outer diameter  342 . 15  of body  342 . The spring tension of link  324  is chosen to securely locate linkage  324  on body  342  during pre-firing handling. In one embodiment, linkage  324  comprises two sheet metal stampings that overlap at the top and bottom (as shown in  FIG. 11 ), and further which are spot welded together in the overlapping area  324 . 9 . 
         [0081]    During firing, the movement by the breech block  22 . 3  of the gun  22  places round  320  into the firing chamber. Contact between the end of barrel  22 . 1  and the front face of linkage  324  forces link  324  to slide aft toward depression  326 . 1 . Since linkage  324  is placed in tension, this movement into an area of reduced diameter (relative to diameter  342 . 15 ) momentarily reduces the amount of tension. As the coaction of the end of the barrel and linkage  324  continues, link  324  is forced to pivot open toward the rear, and climb over ridge  326 . Preferably, the aft face of depression  326 . 1  and the forward face of ridge  326  are sloped to minimize gouging. As the backward action of link  324  continues, it climbs over ridge  326  and relocates on diameter  326 . 2 . 
         [0082]    Regions of body  348  that contact linkage  324  are generally cylindrical and can include one or more milled flats to provide adequate clearance to parts of the gun and ammunition feed tray. Further, although generally cylindrical regions are shown and described, various embodiments of the present invention contemplate other types of surface features (including a plurality of circumferentially-space projections) that support the underside of linkage  324  as described herein as linkage  324  slides aftward over body  348 . 
         [0083]    Round  320  includes a separate telescoping chamber (or base)  348  and mandrill body  332  to allow interchangeability with single shot rounds. The telescoping components needed for autoloading in a machine gun are separate from ring airfoil components. The buttress shoulder on the body of the round which is used to react against the barrel breech chamfer is milled flat to clear the feed tray of the gun and provide free clearance to the link as it is slide back by action of the bolt. 
         [0084]    The embodiment shown in  FIG. 12  illustrates a cross sectional view of an assembled ammunition round  420  as another embodiment. Round  420  includes means  464 . 4  for stopping sabot  462 . As shown in  FIG. 12 , stopping means  464 . 4  includes an oversize washer mounted inbetween support ring  464 . 2  of retainer  464  and rod  442 . 7  of support member  442 . During firing of munition  420 , sabot  462  is pushed forward by combustion gases and is guided by both the inner diameter of barrel  22 . 1  and the outer diameter  442 . 8  of rod  442 . 7 . This guided, forward travel of sabot  462  pushes projectile  480  into the frangible retaining petals of retainer  464 . These petals break, and sabot  462  continues pushing projectile  480  toward the exit of the barrel. The sliding motion of sabot  462  stops when its forward face contacts the aft face of sabot stop  464 . 4 . After contact is made, projectile  480  continues forward and is ejected from the gun barrel. Sabot  462  is retained on rod  442 . 7 . Sabot stop  464 . 4  stops the sabot  462  from exiting the muzzle, and prevents the sabot from being a secondary projectile for both unwanted target impacts and to prevent distraction of the gunner&#39;s sighting ability by the sabot. 
         [0085]      FIGS. 13   a ,  13   b , and  13   c  illustrate views of an assembled ammunition round  520 . Round  520  is the same as round  420 , except that a separate sabot stop  464 . 4  is replaced with a stop  564 . 4  that is molded integrally with retainer  564 . 
         [0086]    Yet another feature of round  520  is the incorporation of a two piece sabot. A first, outer sabot  562  includes an outer diameter  562 . 1  that is in sealing contact with the inner diameter of the gun barrel to discourage leakage of combustion gas. Further, outer diameter  562 . 1  engages the rifling of the barrel and thereby impart spin to outer sabot  562 . Outer sabot  562  includes a plurality of driving features (dogs)  562 . 4  that engage the trailing end of projectile  580 , to thereby also imparts spin to projectile  580 . Yet other embodiments contemplate that either the inner sabot or outer sabot can include the drive dogs that engage the trailing edge of the projectile. 
         [0087]    As best seen in  FIG. 13   b , round  520  further includes an inner sabot  563  having an inner diameter  563 . 3  that is guided along the outer diameter of rod  542 . 7 . The outermost diameter of inner sabot  563  is adapted and configured with driving and sealing features  563 . 6  that interlock with corresponding features  562 . 6  of inner sabot  562 . As indicated by arrows  562 . 7 , the driving features preferably include contacting surfaces adapted and configured to transmit a force that has at least one vector component parallel to the axis of the gun barrel for transmitting propulsive load to the projectile. However, yet other embodiments of the present invention contemplate means for driving that include frictional, interference-type fits between the inner and outer sabots. 
         [0088]      FIG. 13   c  depicts one embodiment of the linkage assembly  524  of munition  520 . Linkage assembly  524  includes a first formed, sheet metal link  524 . 5  coupled to a second, formed, sheet metal link  524 . 6  by a plurality of spotwelds along upper and lower linkage overlapping portions  524 . 9 . Link assembly  524  further includes a T-pin  524 . 7  that is captured on a lateral side of link  524 . 5 . T-pin  524 . 7  is adapted and configured to couple within the slot  524 . 8  of linkage piece  524 . 6 . T-pin  524 . 7  and slot  524 . 8  are examples of complementary-shaped features for coupling to adjacent munitions in a linked belt. 
         [0089]      FIG. 14  illustrates a cross sectional view of the assembled ammunition round  620 , another embodiment of the present invention. Round  620  includes a retainer  664  including a central rod  664 . 6  that threadably couples to threads  646  of support  642 . In one embodiment, retainer  664  further includes a sabot stop  664 . 4  for stopping the forward motion of sabot  662 . In some embodiments, the inner diameter  662 . 2  of sabot  662  is guided by the substantially aligned and parallel outer diameters of rod  642 . 7  and rod  664 . 6 . The present invention contemplates the fastening of a retainer  664  to a support  642  in which either component has male threads, and the other component has female threads. Further, other embodiments contemplate alternate means of fastening retainer  664  to support  642 , including the use of adhesives, and further the use of one-way interlocking features, such as the ratchet and lock features of some types of rivets. In the latter case, retainer  664  would be pressed onto rod  642 . 7  in a non-releasable manner. 
         [0090]      FIG. 15  illustrates a cross sectional view of an assembled ammunition round  720  as another embodiment. Round  720  includes a threaded interface  748 . 1  between body  742  and outer support assembly (base)  748  in which support member  742  includes the male interface and base  748  includes the female interface. Yet other embodiments contemplate other means for coupling body  742  to base  748 , including the use of adhesives, and further the use of a one-way interlocking interface such as an internal ratchet and lock of a rivet. Other coupling ideas include an interference fit between body  742  and  748 . 
         [0091]      FIGS. 16   a ,  16   b ,  16   c ,  16   d ,  16   e ,  16   f ,  16   g , and  16   h  depict an ammunition round  820  according to another embodiment of the present invention. Round  820  includes a base  848  having a central projection  848 . 13  that is accepted within a compartment (or pocket)  842 . 13  within support body  842 . Projection  848 . 13  further includes a central passage  844 . 3  for communicating an ignition pulse from the primer to the explosive charge  844 . 4 . In one embodiment an o-ring seal  842 . 14  resides within a groove of pocket  842 . 13  for sealing of combustion gases. Base  848  includes female threads  848 . 6  that interface with male threads on base  842  (this thread orientation being interchangeable). 
         [0092]      FIG. 16   d  shows a launch support assembly  840  according to one embodiment of the present invention. Assembly  840  is a subassembly that is interchangeable on either single shot or automatic loading bases  848 . In one embodiment, munition  840  includes a retainer  864 , sabot  862 , projectile  880  captured between the retainer and sabot, and a base  842  that supports the retainer and sabot. Subassembly  840  can be coupled to a base by coupling means including threads, bayonet-type connections (such as those used with electrical connectors), adhesives, an interference fit, and/or shear pins (such as cold-rolled pins inserted through the walls. 
         [0093]    The assembled base  848  further includes a telescoping support body  832  which is useful in reloading applications. Body  832  includes a chamber (or pocket)  832 . 13  that accepts within it a concave combustion chamber support  833 . Support  833  further includes within it an internal pocket that accepts a central projection  832 . 15  of body  832 . An o-ring seal  832 . 14  is located within a groove of either projection  832 . 15  or the corresponding pocket of support  833  for sealing of combustion gases. 
         [0094]    Combustion chamber support  833  preferably defines at least a portion of a combustion chamber to house an explosive charge  834 . 4 . A plurality of gas passageways  832 . 5  extend outwardly from the combustion chamber (as best seen in  FIG. 16   f ). In some embodiments, combustion chamber support  833  is an interference fit and is pressed into pocket  832 . 13 . 
         [0095]    In one embodiment, retainer  864  is fabricated from high density polyethylene (HDPE). Projectile  880  is preferably fabricated from Noryl®. Body  842 , sabot  862 , and combustion chamber support  833  are preferably fabricated from a polymer such as ABS. Base body  848  is fabricated from an aluminum alloy such as 7075-T6. Support body  832  is preferably fabricated from aluminum such as 6020-T8. 
         [0096]      FIGS. 17-21  show schematically the firing of a round  820  within a gun barrel  22 . 1 . The following is a description of the firing of ammunition as shown in  FIGS. 17-21 . Upon being on the bolt face in the ready battery position, latched and ready to be fired, the trigger is pulled. The bolt travels forward until the firing pin  22 . 4  is released, about 1″ from the breech face  22 . 3 . 
         [0097]    Referring to  FIG. 18 , the pin strikes the aft telescoping charges primer initiating the propellant; simultaneously an initiation ball  837  is propelled forward to a primer  834 . 1  for the forward payload propelling charge, and the expanding gas reacts against the telescoping piston to open the action and auto load function the gun. 
         [0098]    The forward payload propelling charge expands against the sabot/pusher  862  pushing it forward while fracturing the projectile retainer  864  along one or more separation groove(s) on the central hub of the retainer releasing the sabot and projectile assembly for forward travel. 
         [0099]    Referring to  FIG. 19  the sealing and rotating outer diameter  862 . 1  of sabot  862  seals the propelling gas from the action at the forcing cone of the chamber. The sabot/projectile assembly  160  is pushed along the bore and along the center guide mandrill  842 . 7 , throughout the launch sequence. 
         [0100]    The sabot/projectile assembly travels down the bore to the end of the guide mandrill having spin imparted to the assembly by the action of rifling  22 . 2  in the gun bore  22 . 1  rotating the sabot  862 , which transfers the rotation by the action of drive dogs  862 . 4  on its forward face engaging slots  888  in the tail  892  of the ring airfoil projectile  880 . 
         [0101]    Referring to  FIG. 20 , the front surface of sabot  862  has contacted the aft facing surface of sabot stop  864 . 4 . Sabot  862  is unable to move past stop  864 . 4 , and comes to rest on rod  842 . 7 . However, projectile  880  is not stopped, and continues to fly within barrel  22 . 1 . In those embodiments having a two-piece sabot assembly, one sabot portion is stopped and retained on rod  842 . 7 , and the other portion continues its flight down the barrel, behind projectile  880 . 
         [0102]    The projectile rides a turbulent boundary layer of air between its outer diameter and the bore guiding and centering it until it exits the muzzle. The sabot exits the muzzle at greatly reduced energy. The ring airfoil  80  is free to fly towards the target. The automatic loading features of gun  22  remove the fired round  820  from barrel  22 . 1 . Sabot  862 , since it is retained on member  842 , exists with the spent munition. 
         [0103]      FIGS. 22-26  depict the co-action of spring-loaded link assembly  824  with barrel  22 . 1  during the automatic loading process. As round  820  is brought to the breech of barrel  22 . 1 , the overlapping portions  824 . 9  of link assembly  824  come into contact with and abut against the end  22 . 5  of barrel  22 . 1  (as best seen in  FIG. 22 ). Continued motion of round  820  into barrel  221  causes link  824  to be held in position against barrel end  22 . 5 . As support assembly  848  continue to move into barrel  22 . 1 , the aft most edge of link assembly  824  moves into the region  826 . 1  of reduced diameter, such that link assembly  824  momentarily takes on a conical shape with reduced tension (as best seen in  FIG. 23 ). 
         [0104]      FIG. 24  shows that subsequent motion of round  820  into barrel  22 . 1  continues to move link assembly  824  in sliding motion over shoulder  826  of body  848 . Link assembly  824  thereby takes on a conical shape and increased tension, except in a direction different than that as shown in  FIG. 23 . Referring to  FIG. 25 , the continued motion of round  820  is stopped by the abutment of the forward edge of ridge  826  against chamfer  22 . 6  of barrel  22 . 1 . 
         [0105]    In some embodiments, linkage assembly  824  is supported in a conical shape by both shoulder  826  and further by the diameter  826 . 2  of body  848  immediately aft of shoulder  826 . As shown in  FIG. 26 , linkage  824  continues to slide along the curving and diametrically-reducing aft surface of should  826 , and linkage assembly  824  comes to rest on the aft portion of ridge  826  and on the diameter  826 . 2  of body  848  aft of the ridge. 
         [0106]    The following figures are scaled drawings:  9 ,  10 ,  11 ,  12 ,  13   a ,  14 ,  15 , and  16   a . All of the munitions shown and described herein are applicable to guns ranging from about 36 mm to about 43 mm. In one embodiment, projectiles  80  weigh about 12 to 14 grams, and are launched with a muzzle exit velocity of about 100 mps. However, the invention is not so limited, and these dimensions and scalings are illustrative examples only. 
         [0107]    Although what are shown and described are a variety of munitions including a ring airfoil projectile, the invention is not so limited, and contemplates the use and launching of any kind of projectile, including as non-limiting examples rubber bullets, bean bags, nets, balls, gas canisters, and also including lethal projectiles, and the like. 
         [0108]    While the inventions have been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.