Patent Publication Number: US-2016223302-A1

Title: Ammunition cartridge and chamber, and tools for making and reloading same

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 62/116,099 filed on Feb. 13, 2015. This application is a continuation-in-part of U.S. patent application No. 29/516,665 filed on Feb. 4, 2015. This application is a continuation-in-part of U.S. patent application No. 29/516,668 filed on Feb. 4, 2015. The contents of these three applications are incorporated by reference herein in their entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates to firearms and ammunition. More particularly, this invention relates to a case for an ammunition cartridge, as well as ammunition cartridges that utilize the case. Further, the present invention relates to barrels that are chambered for the case, a sizing die and seating die for reloading used cases, a reamer for reaming a chamber in a barrel blank that may be suitable for ammunition cartridges which utilize the case, and headspace gauges for assessing the suitability of the chambered barrels for use with the ammunition cartridges. 
     BACKGROUND 
     Smaller ammunition cartridges allow sportsman, law enforcement, and the military to carry more ammunition. Accordingly, a need exists for new ammunition cartridges which may be used, for example, with an AR-15 weapon platform that is configured for 9 mm ammunition. 
     SUMMARY 
     Hence, the present invention is directed to a case for an ammunition cartridge, ammunition cartridges that utilize the case, a chambered barrel for firing the ammunition cartridges, a sizing die for reloading used cases, a reamer for reaming a chamber in a barrel blank that is suitable for ammunition cartridges which utilize the case, and headspace gauges for assessing the suitability of the chambered barrels for use with the ammunition cartridges. 
     In one embodiment, a case for an ammunition cartridge may include a tubular member having a central axis which comprises a head which includes a head face that is disposed substantially perpendicular to the central axis. The head further may include an extraction groove adjacent to the head face, the extraction groove circumscribing the central axis. The tubular member, without limitation, may include: a body abutting the head which comprises an internal chamber; a bullet receiving end spaced from the body along the central axis; a convex curved segment abutting the body, the convex curved segment being a circular curve having a first radius of approximately 0.0263 inches; a frusto-conical segment abutting the convex curved segment; and a concave curved segment abutting the frusto-conical segment, the concave curved segment being another circular curve having a second radius of approximately 0.1049 inches. 
     The convex curved segment may include a shoulder-neck junction, the shoulder-neck junction may be spaced from the head face along the central axis by approximately 0.6673 inches. The tubular member at the shoulder-neck junction may have a first reference outer diameter of approximately 0.2626 inches. Also, the tubular member may have an axial length that is measured along the central axis from the head face to the bullet receiving end. The axial length of the tubular member may be substantially equal to or less than 0.846 inches. 
     The concave curved segment may include a body-shoulder junction, the body shoulder junction may be spaced from the head face along the central axis by approximately 0.5699 inches. The tubular member at the body-shoulder junction may have a second reference outer diameter of approximately 0.3676 inches. 
     The bullet receiving end of the tubular member may have an outer diameter of approximately 0.2489 inches. The bullet receiving end may include a mouth of a passage. The passage may extend along the central axis to the internal chamber. The mouth may have an inner diameter of approximately 0.2211 inches. 
     The head further may include a rim abutting the extraction groove, and an opening on the head face, the opening extending toward the body and forming a pocket in the head. The body may include a flash hole connecting the pocket and the internal chamber. The flash hole may have a diameter of approximately 0.08 inches. A primer may be seated in the pocket, and the tubular member may be formed from a brass alloy. 
     A charge of propellant may be disposed in the internal chamber, and a bullet may be seated in the passage to form an ammunition cartridge for a firearm. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       In the accompanying drawings, which form a part of the specification and are to be read in conjunction therewith and in which like reference numerals (or designations) are used to indicate like parts in the various views: 
         FIG. 1  is a perspective view of an exemplary embodiment of an ammunition cartridge in accordance with the present invention; 
         FIG. 2  is a cutaway perspective view of the ammunition cartridge of  FIG. 1 ; 
         FIG. 3  is a perspective view of an exemplary embodiment of a case for an ammunition cartridge in accordance with the present invention; 
         FIG. 4  is another perspective view of the case of  FIG. 3 ; 
         FIG. 5  is a front view of the case of  FIG. 3 ; 
         FIG. 6  is a side view of the case of  FIG. 3 ; 
         FIG. 7  is a rear view of the case of  FIG. 3 ; 
         FIG. 8  is a cutaway perspective view of the case of  FIG. 3 ; 
         FIG. 9A  is a cross-sectional view of the case of  FIG. 3 , along line  9 A- 9 A; 
         FIG. 9B  is an expanded view of a portion of  FIG. 9A ; 
         FIG. 10  is a perspective view of another embodiment of an ammunition cartridge in accordance with the present invention; 
         FIG. 11  is a perspective view of yet another embodiment of an ammunition cartridge in accordance with the present invention; 
         FIG. 12  is a side view of the profiles of the ammunition cartridges of  FIGS. 1, 10 and 11 ; 
         FIG. 13A  is a cross-sectional view of the ammunition cartridge of  FIG. 1 , along line  13 A- 13 A; 
         FIG. 13B  is a cross-sectional view of the ammunition cartridge of  FIG. 10 , along line  13 B- 13 B; 
         FIG. 13C  is a cross-sectional view of the ammunition cartridge of  FIG. 11 , along line  13 C- 13 C; 
         FIG. 14A  is a perspective view of an exemplary embodiment of a cylindrical member which includes a chamber that is configured and dimensioned for use with the case of  FIG. 3  and the ammunition cartridges of  FIG. 12 ; 
         FIG. 14B  is an elevation view of the breech face of the chamber of  FIG. 14A ; 
         FIG. 14C  is a cross-sectional view of the chamber of  FIG. 14 b   , along line  14 C- 14 C; 
         FIG. 14D  is an expanded view of a portion of  FIG. 14C ; 
         FIG. 15  is a perspective view of an exemplary embodiment of a long arm that is configured and chambered for the ammunition of  FIGS. 1, 10 and 11 ; 
         FIG. 16  is a perspective view of the barrel of  FIG. 15 ; 
         FIG. 17  shows a partial cross-section of the barrel of  FIG. 16 , along line  17 - 17 ; 
         FIG. 18  is a cross-sectional view of the breech end of the barrel of  FIG. 18 , along with a chambered ammunition cartridge of  FIG. 1 ; 
         FIG. 19  is a perspective view of an exemplary embodiment of a pistol that is configured and chambered for the ammunition of  FIGS. 1, 10 and 11 ; 
         FIG. 20  is a partially exploded view of the pistol of  FIG. 19 ; 
         FIG. 21  shows a partial cross-section of the barrel of  FIG. 20 , along line  21 - 21 ; 
         FIG. 22  is a cross-sectional view of the breech end of the barrel of  FIG. 20 , along with a chambered ammunition cartridge of  FIG. 1 ; 
         FIG. 23  is a side view of an exemplary embodiment of a reamer which may be used to form a chamber which is configured and dimensioned for firing ammunition cartridges that utilize the case of the present invention; 
         FIG. 24  is a cross-sectional view of the reamer of  FIG. 23 ; 
         FIG. 25  presents a perspective view of the reamer of  FIG. 23 ; 
         FIG. 25A  is a cross-sectional view of the reamer of  FIG. 25 , along line  25 A- 25 A; 
         FIG. 26  is a perspective view of an exemplary press for reloading ammunition cartridges; 
         FIG. 27  is a perspective view of an exemplary embodiment of a sizing die for reloading ammunition cartridges that utilize the case of  FIG. 3 ; 
         FIG. 28  is a cross-sectional view of the sizing die of  FIG. 27 , along line  28 - 28 ; 
         FIG. 29  is a perspective view of an exemplary embodiment of a seating die for reloading ammunition cartridges that utilize the case of  FIG. 3 , the seating die being in an extended configuration; 
         FIG. 30  is a cross-sectional view of the seating die of  FIG. 29 , along line  30 - 30 ; 
         FIG. 31  is another perspective view of the seating die of  FIG. 29 , the seating die being in a retracted configuration; 
         FIG. 32  is a cross-sectional view of the seating die of  FIG. 31 , along line  31 - 31 ; 
         FIG. 33  is a perspective view of a storage box for a reloading die kit in a closed configuration; 
         FIG. 34  is a perspective view of the storage box of  FIG. 33  in an open configuration; 
     
    
    
     DESCRIPTION 
       FIGS. 1 and 2  show an exemplary embodiment of an ammunition cartridge  10  in accordance with the present invention. The ammunition cartridge may include a case  12  and a bullet  14 . The case may include a head  16  and a mouth  18 . The head  16  may include a rim  20  and a groove  22  forward of the rim, as well as a rear shoulder  24 . The case  12  may further include a body  26  adjacent the head, a neck  28  abutting the mouth, and a shoulder  30  disposed between the body  26  and the neck  28 . The bullet  14  may be seated in the mouth  18  of the case. The bullet  14  may include a ballistic tip  32 . 
     Referring to  FIGS. 3, 4, 6, 8 and 9A , the case  12  may define a generally elongated cylindrical member. The exterior profile of the generally elongated cylindrical member may possess a bottleneck shape. The head  16  of the case may have approximately the same maximum outer dimension as the base  34  of the body  26 . The outer dimension of the body  26 , however, may taper gradually from the base  34  to the shoulder  30 . The shoulder  30  may taper down to the neck  28 . 
     As shown in  FIG. 9A , the shoulder  30  may include a frusto-conical segment  36 . Also, the shoulder  30  may include a curved segment of convex shape  38  that connects the body  26  and the frusto-conical segment  36 . The curved segment of convex shape  38  may be a round that is formed by a circular curve having a center point C 1  and radius R 1 . In this embodiment, radius R 1  measures 0.0263 inches. Referring to  FIG. 9B , the point of intersection PI 1  of the tangent lines  39 A,  39 B of the circular curve may define a reference dimension for the case. As shown in  FIG. 9A , the axial distance L 4 , measured from the head face  40  to the point of intersection PI 1 , may define a location on the circular curve  39 C that delineates the junction of the base and shoulder of the case. The diameter of the case at this location  39 C may define another reference dimension for the case, namely the shoulder diameter D 4  (i.e., the diameter of the case where the shoulder ends). 
     The case  12  may include another curved segment of concave shape  42  that connects the frusto-conical segment  36  and the neck  28 . The curved segment of concave shape  42  may be a fillet that is formed by a circular curve having a center point C 2  and radius R 2 . In this embodiment, radius R 2  measures 0.1049 inches. As shown in  FIG. 9B , the point of intersection PI 2  of the tangent lines  43 A,  43 B of the circular curve may define a reference dimension for the case. As shown in  FIG. 9A , the axial distance L 5  measured from the head face  40  to the point of intersection PI 2  may define a location on the circular curve  43 C that delineates the junction of the shoulder and neck of the case. The diameter of the case at this location  43 C may define yet another reference dimension for the case, namely the headspace diameter D 5  (i.e., the diameter of the case where the shoulder starts). 
     The neck  28  of the case further may include a cylindrical portion of generally constant outer diameter D 6  which extends from the shoulder to the mouth end. The outer diameter of the neck  28 , however, may taper gradually to the mouth  18  of the case in order to promote a better interface between a bullet and the case. Accordingly, the bottleneck shape of case may include a gradual reduction in the outer dimension of the cartridge case from the base diameter to the mouth. 
     As shown in  FIGS. 2, 4, 7, 8 and 9A , the case  12  may include a bore  44  on the head face  40  that extends toward the body  26 . The bore  44  may terminate at an end wall  46 . Referring to  FIGS. 2, 8 and 9 , the bore  44  and end wall  46  may form a pocket  48  for receiving a primer  50 . The primer  50  may be a commercial or military grade primer. For example, the primer may be a standard rifle primer manufactured by CCI Ammunition of Lewiston, Id. 
     Further, the case  12  may include an interior chamber  52 . The lateral bounds of the interior chamber may be defined by an inner sidewall  54  of the case. The lower bounds of the interior chamber  52  may be defined by a seat  56  near the base of the case. The interior chamber  52  and the pocket  48  may be connected by one or more passages (or flash-holes)  58  that extend from the pocket end wall  46  through the seat  56 . 
     Referring to  FIGS. 2, 13A, 13B, and 13C , the interior chamber  52  may form a receptacle for containing a charge of smokeless propellant  60 . The propellant(s) may be matched to each specific load for a desired pressure, velocity and/or accuracy. Additionally, the propellant(s) may be custom blended for each individual load to enhance value, performance or consistency lot to lot. 
     Exemplary dimensions for the case of  FIG. 3  are shown in  FIG. 9A  and presented in Table 1 (below). Preferably, the case  12  may be formed from brass. Most preferably, the case  12  may be formed from military brass. The case, however, may be formed from other materials including, without limitation, aluminum, copper, steel, other metal alloys, polymer materials, and combinations thereof. Generally, other materials may be used to form the case provided that the other materials are resistant to corrosion, can withstand the internal pressures generated by cartridge operation, and can allow for manipulation via extraction and ejection without tearing. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Exemplary Case Dimensions 
               
            
           
           
               
               
               
            
               
                 Description 
                 Parameter 
                 Measurement (a) 
               
               
                   
               
            
           
           
               
               
               
            
               
                 Rim thickness, overall 
                 L1 
                 0.0431 
               
               
                 Rim thickness 
                 L2 
                 0.0282 
               
               
                 Extraction groove thickness 
                 L3 
                 0.0257 
               
               
                 Axial length from head face to 
                 L4 
                 0.5699 
               
               
                 base-shoulder junction (b) 
               
               
                 Axial length from head face to 
                 L5 
                 0.6673 
               
               
                 shoulder-neck junction (b), (c) 
               
               
                 Case length 
                 L6 
                 0.8461 
               
               
                 Rim diameter 
                 D1 
                 0.3676 
               
               
                 Extraction groove diameter 
                 D2 
                 0.3237 
               
               
                 Base diameter 
                 D3 
                 0.3727 
               
               
                 Base-Shoulder junction diameter 
                 D4 
                 0.3676 
               
               
                 Shoulder-Neck junction diameter (c) 
                 D5 
                 0.2626 
               
               
                 Mouth, outer diameter 
                 D6 
                 0.2489 
               
               
                 Mouth, inner diameter 
                 D7 
                 0.2211 
               
               
                 Primer pocket, inner diameter 
                 D8 
                 0.1750 
               
               
                 Flash-hole, inner diameter 
                 D9 
                 0.0800 
               
               
                 Radius of circular curve, convex 
                 R1 
                 0.0263 
               
               
                 segment (round) 
               
               
                 Radius of circular curve, concave 
                 R2 
                 0.1049 
               
               
                 segment (fillet) 
               
               
                 Shoulder taper angle 
                 α 1   
                 29.8970° 
               
               
                 Head taper angle 
                 α 2   
                 25.5640° 
               
               
                   
               
               
                 Notes: 
               
               
                 (a) Unless otherwise noted, unit dimensions measured in inches 
               
               
                 (b) Dimensions are to intersection of tangent lines 
               
               
                 (c) Reference dimension 
               
               
                 (d) Case trim length for reloading: 0.838 inches; maximum case length for reloading: 0.840 inches. 
               
            
           
         
       
     
       FIGS. 2, 10 and 11 , respectively, show three exemplary ammunition cartridges  62 ,  64 ,  66 , which utilize different bullets  70 ,  72 ,  74  in combination with the case  12  of  FIG. 3  to form an ammunition cartridge  10  in accordance with the present invention. 
     In  FIGS. 1 and 13A , the bullet  68  is a 35 grain, .22 caliber, V-MAX®, bullet manufactured by Hornady Manufacturing Company, 3625 West Old Potash Hwy, Grand Island, Nebr. 68803. This bullet  68  includes a polymer tip  32 , a lead core  33 , and a surrounding guilding metal jacket  35 . When used in combination with the case  12  of  FIG. 3 , the bullet  68  may form a fragmentation ammunition cartridge. Loading data for a preferred embodiment of an ammunition cartridge using the 35 grain, .22 caliber V-MAX® bullet and the case of  FIG. 3  is presented in Table 2 (below). 
     Muzzle velocity for the bullet  68  of the preferred embodiment of the fragmentation ammunition cartridge  62  was measured using a “Master-Chrony” chronograph manufactured by SHOOTING CHRONY INC., 3840 East Robinson Rd., PMB #298, Amherst, N.Y. 14228. The cartridge  62  was fired from a 9 mm AR-15 platform with a 16-inch long barrel that was specifically chambered for the case  12  (see e.g.,  FIG. 14C ). The bore of the barrel included a 1 in 9 twist rifling. Based on measurements from a 5 shot group, the 35 grain bullet achieved an average muzzle velocity of substantially equal to or greater than 2,800 feet per second. 
     In  FIGS. 10 and 13B , the bullet  70  is a 36 grain, Barnes .22 caliber Varmit Grenade® bullet manufactured by Barnes Bullets, LLC. 38 N Frontage Rd Mona, Utah 84645. This bullet  70  may include a hollow cavity  71  and frangible core  73  surrounded by a gilding metal jacket  35 . The frangible core  73  may be formed from copper and tin powdered metal. When used in combination with the case  12  of  FIG. 3  this bullet  70  may form a frangible ammunition cartridge  64 . Loading data for a preferred embodiment of an ammunition cartridge using the 36 grain, .22 caliber, Varmit Grenade® bullet  70  and the case of  FIG. 3  is presented in Table 2 (below). 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Exemplary Ammunition Cartridges 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                   
                   
                 Muzzle 
                   
                   
               
               
                   
                   
                 Bullet 
                 velocity(f) 
                   
                 Bullet 
               
               
                   
                   
                 Weight 
                 (feet per 
                 Charge 
                 (Manufacturer, 
               
               
                 Cartridge 
                 Bullet Construction 
                 (grains) 
                 second) 
                 (grains) 
                 Cal., Type, Item#) 
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 Fragmentation 
                 Polymer tip, lead 
                 35 
                 2,800 
                 5.6(c) 
                 Hornady(a), 
               
               
                   
                 core, surrounded by 
                   
                   
                   
                 22 cal., 
               
               
                   
                 a guilding metal 
                   
                   
                   
                 “V-max,” 
               
               
                   
                 jacket, flat base 
                   
                   
                   
                 22252 
               
               
                 Frangible Core 
                 Hollow-cavity, 
                 36 
                 2,600 
                 5.8(c) 
                 Barnes(b), 
               
               
                   
                 frangible core 
                   
                   
                   
                 22 cal., 
               
               
                   
                 (copper-tin 
                   
                   
                   
                 “Varmint 
               
               
                   
                 powdered metal 
                   
                   
                   
                 Grenade,” 
               
               
                   
                 core) surrounded by 
                   
                   
                   
                 22436 
               
               
                   
                 a guilding metal 
               
               
                   
                 jacket, flat base 
               
               
                 Subsonic 
                 Full Metal Jacket 
                 55 
                 950 
                 2.5(d) 
                 Generic 
               
               
                   
                 (copper and lead) 
                   
                   
                   
                 22 cal. 
               
               
                   
                   
                   
                   
                   
                 FMJ 
               
               
                   
               
               
                 Notes: 
               
               
                 (a)Hornady Manufacturing Company, 3625 West Old Potash Hwy, Grand Island, NE 68803 
               
               
                 (b)Barnes Bullets, LLC. 38 N Frontage Rd Mona, UT 84645 
               
               
                 (c)Hi-Skor 800-X double base smokeless propellant manufactured by Hodgdon Powder Company 6430 Vista Drive, Shawnee, KS 66218 
               
               
                 (d)HS-6 ® double base smokeless propellant distributed by Hodgdon Powder Company6430 Vista Drive, Shawnee, KS 66218 
               
               
                 (e) Muzzle velocity measured in fps with an F-1 MASTER-CHRONY chronograph manufactured by SHOOTING CHRONY INC., 3840 East Robinson Rd., PMB # 298, Amherst, NY 14228 
               
               
                 (f)Based on measurements from 5 shot groups, the bullets from each respective cartridge achieved an average muzzle velocity of substantially equal to or greater than the reported value. 
               
            
           
         
       
     
     Muzzle velocity for the bullet  70  of the preferred embodiment of the frangible ammunition cartridge  64  was measured using a Master-Chrony chronograph manufactured by SHOOTING CHRONY INC., 3840 East Robinson Rd., PMB #298, Amherst, N.Y. 14228. The cartridge  64  was fired from a 9 mm AR-15 platform with a 14-inch long barrel that was specifically chambered for the case (see e.g.,  FIG. 14C ). The bore of the barrel included a 1 in 9 twist rifling. Based on measurements from a 5 shot group, the 36 grain bullet  70  achieved an average muzzle velocity of substantially equal to or greater than 2,600 feet per second. 
     In  FIGS. 11 and 13C , the bullet  72  is a 55 grain, .22 caliber, generic FMJ (full metal jacket) bullet. 
     When used in combination with the case  12  of  FIG. 3 , this bullet  72  may form a subsonic ammunition cartridge  66 . Loading data for a preferred ammunition cartridge using the 55 grain, .22 caliber, generic FMJ bullet  72  and the case  12  of  FIG. 3  are presented in Table 2 (below). 
     Muzzle velocity for the bullet  72  of the preferred embodiment of the subsonic ammunition cartridge  66  was measured using a Master-Chrony chronograph manufactured by SHOOTING CHRONY INC., 3840 East Robinson Rd., PMB #298, Amherst, N.Y. 14228. The cartridge was fired from a 9 mm AR-15 platform with a 14-inch long barrel that was specifically chambered for the case (see e.g.,  FIG. 14C ). The bore of the barrel included a 1 in 9 twist rifling. Based on measurements from a 5 shot group, the 55 grain bullet  72  achieved an average muzzle velocity of substantially equal or greater than 950 feet per second. 
     Moreover, other bullets may be used in combination with the case  12  of  FIG. 3 . For example, without limitation, a 55 grain, .22 caliber, soft point bullet may be used in combination with the case  12  of  FIG. 3  as a substitute for the generic FMJ bullet in the subsonic ammunition cartridge described above. 
       FIG. 13A  shows a schematic view of the 35 grain, .22 caliber. V-MAX® bullet  68  seated within the case  12  of  FIG. 3 . The total cartridge length L TC  is 1.165 inches. In the preferred embodiment, 35 grain bullet ammunition cartridge  62  includes a charge of 5.5 grains of smokeless propellant  60 . Preferably, the smokeless propellant  60  is Hi-Skor 800-X (a double-base, smokeless propellant) manufactured by Hodgdon Powder Company, 6430 Vista Drive, Shawnee, Kans. 66218. 
       FIG. 13B  shows a schematic view of the 36 grain, .22 caliber, Varmit Grenade® bullet  70  seated within the case  12  of  FIG. 3 . The total cartridge length L TC  is 1.165 inches. In the preferred embodiment, the 36 grain bullet ammunition cartridge  64  includes a charge of 5.8 grains of smokeless propellant  60 . Preferably, the smokeless propellant  60  is Hi-Skor 800-X (a double-base, smokeless propellant) manufactured by Hodgdon Powder Company, 6430 Vista Drive, Shawnee, Kans. 66218. 
       FIG. 13C  shows a schematic view of the 55 grain, .22 caliber, FMJ bullet  72  seated within the case of  FIG. 3 . The total length L TC  of the 55 grain bullet ammunition cartridge  66  is 1.165 inches. In the preferred embodiment, the 55 grain bullet ammunition cartridge  66  includes a charge of 2.5 grains of smokeless propellant  60 . Preferably, the smokeless propellant is HS-6® (a double-base, smokeless propellant) manufactured by Hodgdon Powder Company, 6430 Vista Drive, Shawnee, Kans. 66218. 
     Referring to  FIG. 12 , an ammunition cartridge (e.g.,  62 ,  64 , and  66 ) that utilizes the case  12  of  FIG. 3  may have nominal dimensions intended to establish a standard cartridge type. Variations from the nominal dimensions may be tolerated by limited amounts. For example, diameters in  FIG. 12  may have a tolerance of +0.000/−0.004 inch, except as otherwise noted. Table 3 (below) presents an exemplary set of nominal dimensions and tolerances for the standard cartridge type of  FIG. 12 . 
     
       
         
           
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                 Nominal Dimensions for Exemplary Cartridge Type 
               
            
           
           
               
               
               
               
            
               
                   
                   
                 Dimension 
                 Tolerance 
               
               
                 Description 
                 Parameter 
                 (a) 
                 (a) 
               
               
                   
               
               
                 Rim thickness, overall 
                 L RMT   
                  0.045 
                  −0.010 
               
               
                 Rim thickness 
                 L RM   
                  0.027 
                  −0.010 
               
               
                 Extraction groove thickness 
                 L EG   
                  0.030 
                  +0.010 
               
               
                 Axial length from head face to base- 
                 L HBSJ   
                  0.5699 
                 — 
               
               
                 shoulder junction (b) 
               
               
                 Axial length from head face to 
                 L HSNJ   
                  0.6673 
                 — 
               
               
                 shoulder-neck junction (b), (c) 
               
               
                 Case length 
                 L CL   
                  0.8461 
                  −0.020 
               
               
                 Rim diameter 
                 D RIM   
                  0.378 
                  −0.010 
               
               
                 Head Face/Extraction groove 
                 D HF/EG   
                  0.332 
                  −0.020 
               
               
                 diameter 
               
               
                 Base diameter 
                 D B   
                  0.3727 
                 — 
               
               
                 Base-Shoulder junction diameter (b) 
                 D BSJ   
                  0.3676 
                 — 
               
               
                 Shoulder-Neck junction diameter (b), 
                 D SNJ   
                  0.2626 
                 — 
               
               
                 (c); headspace 
               
               
                 Mouth, outer diameter 
                 D MO   
                  0.2490 
                 — 
               
               
                 Radius of circular curve, convex 
                 R1 
                  0.0263 
                 — 
               
               
                 segment (round) 
               
               
                 Radius of circular curve, concave 
                 R2 
                  0.1049 
                 — 
               
               
                 segment (fillet) 
               
               
                 Shoulder taper angle 
                 α 1   
                 29.8970° 
                 — 
               
               
                 Head taper angle 
                 α 2   
                 25.5640° 
                 — 
               
               
                 Rim taper angle 
                 α 3   
                 35° 
                 +20° 
               
               
                 Cartridge length 
                 L TC   
                  1.165 
                  −0.002 
               
               
                 Bullet diameter 
                 D PRJ   
                  0.224 
                  −0.001 
               
               
                   
               
               
                 Notes: 
               
               
                 (a) Unless otherwise noted, unit dimensions measured in inches 
               
               
                 (b) Dimensions are to intersection of lines 
               
               
                 (c) Reference dimension 
               
            
           
         
       
     
       FIG. 14A  is a perspective view of a cylindrical member  74  that includes a chamber that is configured and dimensioned for ammunition cartridges that utilize the case  12  of  FIG. 9A , as well as the illustrative standard cartridge type disclosed in  FIG. 12 . The cylindrical member  74  may include a breech end  76  and a distal end  78 . The cylindrical member  74  may include a chamber  80  and a bore  82 . Collectively, the chamber  80  and the bore  82  may extend through the cylindrical member  74  from the breech end  76  to the distal end  78  along a central axis  84 . The chamber  80  may include a body segment  86 , a shoulder segment  88 , a neck segment  90 , and a throat segment (or free bore)  92 . The bore  82  may extend from the distal side of the throat segment  92  to the distal end  78 . 
       FIG. 14B  is an elevation view of the breech end  76  of the cylindrical member  74  of  FIG. 14A . Visible within the cylindrical member  74  is the body segment  86 , shoulder segment  88 , neck segment  90 , and the throat segment (or free bore)  92  of the chamber  80 . Also, visible from the breech end  76  is the bore  82 . 
       FIG. 14C  is a cross-sectional view of the cylindrical member of  FIG. 14B , along line  14 C- 14 C. 
     The cross-section  94  of the cylindrical member may include an exterior profile  96 . The exterior profile  96  may be symmetrical about the central axis  84 . Although the exterior profile  96  may have uniform dimension as shown in  FIG. 14C , the exterior profile of the cylindrical member may be non-uniform. 
     The chamber  80  may extend along the central axis  84  from the breech face  98  of the cylindrical member  74  toward the distal end  78  of the cylindrical member. The bore  82  may connect the chamber  80  to the distal end  78  of the cylindrical member. Further, the cross-section  94  may include an interior profile  100  that is symmetrical about the central axis  84 . The interior profile  100  of the chamber may include a body segment  86 , a shoulder segment  88 , a neck segment  90 , and a throat segment (or free bore)  92 . The bore  82  may include a cross-sectional profile that is symmetrical about the central axis  84 . Preferably, the bore  82  may include rifling. 
     The chamber  80  may extend along the central axis  84  from the chamber base (S (CB) )  102  to the base-shoulder junction (S BSJ )  104 . The shoulder segment  88  may extend along the central axis  84  from the base-shoulder junction (S BSJ )  104  to the shoulder-neck junction (S SNJ )  106 . The profile of the shoulder segment  88  may include a concave circular curve  108 , a straight line segment  110 , and a convex circular curve  112 . 
     Referring to  FIG. 14B , the concave circular curve  108  may begin at a first point of curvature PC 1  and end at a first point of tangency PT 1 . The concave circular curve  108  may have a center point C 1  and a radius R 1 . In this embodiment, the radius R 1  may be 0.0263 inches. The point of intersection PI 1  of the tangents  113 A,  113 B may define a reference point. The point of intersection PI 1  may be spaced from the breech face  98  by axial length L P11 . The point  113 C on the concave curve  108  that is spaced from the breech face  98  by a distance equal to the axial length L PI1  may be defined as the base-shoulder junction (S BSJ ) of the chamber. Referring to  FIG. 14C , the diameter of the chamber  80  at the base-shoulder junction (S BSJ )  104  may be a reference dimension for the chamber. Namely, the base-shoulder junction diameter D BSJ  of the chamber. 
     One end of the straight line segment  110  of the shoulder segment  88  profile may connect to the first point of tangency P T1  of the concave circular curve  108 . The straight line segment  110  may form a shoulder angle β 1  with respect to the central axis  84 . In this embodiment, the shoulder angle β 1  is approximately 29.8970 degrees. The other end of the straight line segment  110  may connect to the convex circular curve  112 . 
     Referring to  FIG. 14D , the convex circular curve  112  may begin at a second point of curvature PC 2  and may end at a second point of tangency PT 2 . The convex circular curve  112  may have a center point C 2  and a radius R 2 . In this embodiment, the radius R 2  is approximately 0.1049 inches. The point of intersection PI 2  of the tangents  113 A,  113 B may define a second reference point. The point of intersection PI 2  may be spaced from the breech face  98  by an axial length L P12  ( FIG. 14C ). The point on the convex curve  112  that is spaced from the breech face  98  by a distance equal to the axial length L PI2  may be a datum  113 C for defining the headspace of the chamber. The diameter of the chamber at the datum  113 C may be another reference dimension for the chamber. Namely, the headspace diameter D SNJ  of the chamber. Referring to  FIG. 14C , the datum also may define the end of the shoulder segment (or shoulder-neck junction (S SNJ ))  106  of the chamber. 
     The neck segment  90  may begin at the shoulder neck junction (S SNJ )  106  and continue through the point of tangency PT 2  to the neck-throat junction (S NTJ )  148 . The portion of the neck segment  90  extending from the point of tangency PT 2  to the neck-throat junction (S NTJ )  148  may be linear, and thus the diameter of chamber at the neck-throat segment D NTJ  may be constant along the linear portion of the neck segment  90 . 
     The throat segment  92  may taper down from the neck-throat junction (S NTJ )  148  to the throat-bore junction (S TBJ )  150 . In this embodiment, the axial length of the free bore L FB  may be sufficiently short such that the bullet of the chambered cartridge may span the full axial length of the throat L FB  and project into the bore  82 . The bore  82  may have a diameter D B  of 0.2320 inches. Preferably, the bore  82  may include rifling. The rifling may include 6 grooves that have a diameter D G  of 0.2510 inches. The preferred rifling  156  may further exhibit a 1 in 9 twist. Measured dimensions for the chamber  80  are shown in  FIG. 14C  and presented in TABLE 4 (below). 
       FIG. 15  depicts an AR-15 weapon platform  162  that is configured for 9 mm ammunition. The barrel  164  of the AR-15 weapon platform, however, may be chambered for the ammunition cartridge of  FIGS. 1, 10, 11 and 12 . The barrel  164  may be configured for straight blowback operation. The AR-15 weapon platform  162  may be capable of semi-automatic and full automatic modes. 
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 Measured Chamber Dimensions 
               
            
           
           
               
               
               
            
               
                 Description 
                 Parameter 
                 Measurement (a) 
               
               
                   
               
               
                 Length of axial distance from BF to PI 1   
                 L PI1   
                 0.4304 
               
               
                 Length of axial distance from BF to PI 2 ; 
                 L PI2   
                 0.5278 
               
               
                 (b) 
               
               
                 Length of axial distance from BF to S NTJ   
                 L BFNTJ   
                 0.7578 
               
               
                 Length of axial distance from BF to S TBJ   
                 L BFTBJ   
                 0.7727 
               
               
                 Length of axial distance from S NTJ  to S TBJ   
                 L FB   
                 0.0149 
               
               
                 Diameter at base of chamber (S CB ) 
                 D CB   
                 0.3765 
               
               
                 Diameter at base-shoulder junction (S BSJ ) 
                 D BSJ   
                 0.3717 
               
               
                 Diameter at shoulder-neck junction (S SNJ ); 
                 D SNJ   
                 0.2596 
               
               
                 (b) 
               
               
                 Diameter at neck-throat junction (S NTJ ) 
                 D NTJ   
                 0.2510 
               
               
                 Diameter of bore 
                 D B   
                 0.2320 
               
               
                 Diameter of rifling grooves 
                 D G   
                 0.2510 
               
               
                 Radius of concave circular curve 
                 R 1   
                 0.0263 
               
               
                 Radius of convex circular curve 
                 R 2   
                 0.1049 
               
               
                   
               
               
                 Notes: 
               
               
                 (a) Unless otherwise noted, unit dimensions measured in inches 
               
               
                 (b) Headspace dimensions 
               
            
           
         
       
     
     In general, the cycle of straight blowback operation may begin when the cartridge is fired. With an open-bolt cycle, the bolt may be held by the trigger sear to the rear and the recoil spring may be compressed. Pulling the trigger may release the sear; the action spring may then propel the bolt forward, which may strip a round from the feed system along the way. The bolt may carry the new cartridge into the chamber and at the end of its travel the firing pin may fire the primer and ignite the propellant. The pressure of expanding gases from the propellant may send the bullet down the barrel and at the same time may apply an opposite force to the cartridge case against the breech face of the bolt. The breech is kept sealed momentarily by the internal pressure of the cartridge case against the chamber and the inertia of the bolt. Then, momentum transferred to the case and bolt from the expanding gases moves the case and bolt to the rear. The momentum of the bolt is gradually transferred to the body of the gun and the shooter&#39;s body as the recoil spring is compressed. As the bolt travels back, the spent cartridge case is extracted and ejected, and the firing mechanism is cocked by the rearward travelling bolt. The bolt eventually reaches a velocity of zero and the kinetic energy from the recoil impulse is now stored in the compressed spring. The cycle repeats until the last round is expended or the trigger is released engaging the sear to hold the bolt in the rear (open-bolt) position. 
     Referring to  FIG. 16 , the barrel  164  may include a breech end  166  and a muzzle end  168 . The breech end  166  may include a breech (i.e., a chamber opening)  170  and a surrounding breech face  98 . Areas of the barrel  164  adjacent to muzzle end  168  may be threaded  174  for receiving a flash hider, compensator, suppressor, or other suitable tactical accessory or part. Although, the radial dimension of the barrel&#39;s exterior surface  176  may vary along the length of the barrel, the barrel&#39;s exterior surface may have generally constant radial dimension. Spaced from the breech end, however, may be a circumferential ring  178  that may be formed integrally with the barrel. The circumferential ring  178  may be a locking ring that may be used to secure the barrel  164  to an upper receiver of the firearm. 
     Referring to  FIG. 17 , the barrel may include a breech face  98 , a breech  170  that provides access to the barrel&#39;s chamber, a chamber  80 , and a bore  82 . The chamber  80  may be configured and dimensioned in accordance with  FIG. 14C , and thus may include a profile that comprises a body segment  86 , a shoulder segment  88 , a neck segment  90 , and a throat segment  92 . The barrel  164 , however, may include an optional tapered feed section  180  disposed between the breech face  98  and the body segment  86  of the chamber. The feed section  180  may facilitate loading of ammunition cartridges into the chamber due to the increased diameter of the feed section at the breech end. 
     Although the body segment  86  may be shorter in length than disclosed in  FIG. 14C , the diameter D BSJ  at the base-shoulder junction (S BSJ ) may be positioned at the same distance L PI1  from the breech face. Similarly, the chamber  80  may have the same headspace dimensions (i.e., L PI2  and D SNJ ) and shoulder geometry as disclosed in  FIG. 14C . Additionally, the neck segment  90  and throat segment  92  may be configured and dimensioned within the barrel  164  as disclosed in  FIG. 14C . 
       FIG. 18  shows the barrel of  FIG. 17  chambered with an exemplary ammunition cartridge  62 , along with selected dimensions of the ammunition cartridge  62 . For example, the axial length from the head face  40  to the base-shoulder junction L 4  is shown, along with the base-shoulder junction diameter D 4 . Additionally, the axial length from the head face  40  to the shoulder-neck junction (or headspace length) L 5  of the cartridge is depicted, along with the diameter of the shoulder-neck junction (or headspace diameter) D 5 . The axial length of the case L 6  is shown, as well as the total axial length L of the ammunition cartridge. 
     Generally, the ammunition cartridge  62  may fit into the chamber  80  with approximately 200,000 th  of an inch (0.002 inches) clearance. A clearance of approximately 0.002 inches between the unfired ammunition cartridge and the chamber may allow the case to be readily loaded into the chamber for firing, allow for proper sealing of the chamber by an expanded case during firing of the ammunition cartridge, and subsequent to firing of the ammunition cartridge may allow the case to contract sufficiently to facilitate extraction by the bolt group assembly. 
     Moreover, a generally consistent clearance between unfired ammunition cartridge cases and the chamber may facilitate safe and reliable operation of the firearm, as well as facilitate consistency of external ballistic parameters. Also, the bullet  68  may rest against the lands of the rifled bore when the ammunition cartridge is chambered. Further still, the bolt group assembly  163  may abut the barrel  164  and enclose the head  16  of the ammunition cartridge. This may indicate that the headspace of the cartridge is not too long for the chamber. 
     Generally, the barrel  164  may range in length from approximately 8 inches to approximately 20 inches, including standard barrel lengths of 10.5 inches, 14.5 inches, 16 inches, and 18 inches. Preferably, the barrel  164  may have a rifling of approximately one and nine twist. Although the barrel of  FIG. 18  is configured for use with a 9 mm AR-15 platform, the barrel  164  may be configured for use in other long arms or hand guns. 
     Referring to  FIG. 19 , a barrel that is chambered in accordance with  FIG. 14C  may be configured for use with a pistol  182 . For instance, the pistol  182  may be a 9 mm Glock® 22. As shown in  FIG. 20 , the pistol  182  may include a frame  184 , a slide  186 , a barrel  188 , a recoil spring guide rod  190 , and a recoil spring  192 . In this embodiment, the barrel  188  may be chambered in accordance with the chamber  80  of  FIG. 14C . Although, the recoil spring  192  may be customized to accommodate the recoil of the ammunition cartridges of  FIGS. 1, 10 and 11 , the remaining components of the pistol  182  may be original manufacturer parts. 
     Referring to  FIG. 21 , the barrel  188  may include a feed ramp  194 , breech face  98 , a breech  170  that provides access to the barrel&#39;s chamber, a chamber  80 , and a bore  82 . The feed ramp  194  may facilitate loading of ammunition cartridges into the chamber. The chamber  80  may be configured and dimensioned in accordance with  FIG. 14C , and thus may include a profile that includes a body segment  86 , a shoulder segment  88 , a neck segment  90 , and a throat segment  92 . Hence, the base-shoulder junction (S BSJ )  104  may be positioned at the same distance L PI1  from the breech face  98  and may include the same diameter D BSJ  as the chamber shown in  FIG. 14C . Similarly, the chamber  80  may have the same headspace dimensions (i.e., L PI2  and D SNJ ) and shoulder geometry as disclosed in  FIG. 14C . Additionally, the neck segment  90  and throat segment  92  may be configured and dimensioned within the barrel  188  as disclosed in  FIG. 14C . 
       FIG. 22  shows the barrel  188  of  FIG. 21  chambered with an ammunition cartridge of  FIG. 1 . The barrel  188  may be positioned within the slide  186 , the extractor  196  may be interlocked with the head  16  of the ammunition cartridge, and the firing pin  198  may be adjacent to the primer pocket  48 . Reference dimensions of the ammunition cartridge  62  are indicated on the drawing. For example, the axial length measured from the head face  40  to the base-shoulder junction L 4  of the cartridge, as well as the base-shoulder junction diameter D 4  are shown. Additionally, the axial length from the head face  40  to the shoulder-neck junction (or headspace length) L 5  of the cartridge, as well as the diameter of the shoulder-neck junction (or headspace diameter) D 5  are shown. Moreover, the case length (or axial length measured from the head face  40  to the mouth  18 ) L 6  is shown. The total length L of the ammunition cartridge is also depicted. 
     Generally, the ammunition cartridge  62  may fit into the chamber  80  with approximately 200,000 th  of an inch (0.002 inches) clearance. A clearance of approximately 0.002 inches between the unfired ammunition cartridge  62  and the chamber  80  may allow the case to be readily loaded into the chamber for firing, allow for proper sealing of the chamber by an expanded case during firing of the ammunition cartridge, and subsequent to firing of the ammunition cartridge may allow the case to contract sufficiently to facilitate extraction by the bolt group assembly. Moreover, a generally consistent clearance between unfired ammunition cartridge cases and the chamber may facilitate safe and reliable operation of the firearm, as well as facilitate consistency of external ballistic parameters. Also, the bullet  68  may rest against the lands of the rifled bore when the ammunition cartridge is chambered. Further still, the bolt group assembly may abut the barrel and enclose the head of the ammunition cartridge. This is an indication that the headspace of the cartridge is not too long for the chamber. 
     Generally, the pistol barrel  188  may range in length from approximately 3 inches to approximately 8 inches, including standard barrel lengths of 3.77 inches, 4.00 inches, 4.50 inches, and 5.00 inches, and 6.80 inches. Preferably, the barrel  188  may have a rifling of approximately one and nine twist. Although the barrel  188  may be configured for use with a 9 mm Glock® 22 platform, other barrels may be configured for use in different pistols. For instance, without limitation, the barrel  188  and spring  192  may be adapted for use in a Colt  1911  pistol. 
     Preferably, the barrels  164 ,  188  of  FIGS. 21 and 22  may be formed from barrel steel. For example, chrome molybdenum steel (e.g., 4140, 4150 and 4340), chrome moly vanadium steel (e.g., 4150V), or stainless steel (e.g., 416R). The barrel steel may adhere to Military Specification (Mil-B-11595) dated Jun. 7, 1998 for Bar, Metal, and Blanks (under 2 inches in diameter) for Barrels of Small Arms Weapons. Other suitable barrel materials also may be used. The barrels may include a coating. For example, the barrels may include, without limitation, a nitride coating or a phosphate coating. 
       FIG. 25  depicts an exemplary embodiment of a chamber reamer  200  for forming the chamber  80  of  FIG. 14  in a barrel blank. The chamber reamer  200  also may be used to form interior working surfaces of reloading dies (see e.g.,  FIGS. 26-32 ). The chamber reamer  200  may include a shank  202  that includes a proximal end  204  and a distal end  206 . The proximal end  204  may include a tang  208  for securing the shank  202  to a powered cutting tool (e.g. a lathe). The distal end  206  may include a pilot  210  that may be sized for the bore  82  of the barrel and which may guide the chamber reamer  200  as it is advanced into the barrel blank. The chamber reamer  200  may include a cylindrical body  212  between the tang  208  and the pilot  210  that includes a set of generally parallel cutting edges  214 . Referring to  FIG. 25A , each cutting edge  216  may include a land  216  and flute  218 . In the exemplary embodiment, the chamber reamer  200  includes six cutting edges  214 . 
     Referring to  FIG. 23 , the chamber reamer  200  may have a central axis  220  and the cylindrical body  212  may taper in diameter from the shank  202  to the pilot  210 . The chamber reamer  200  may include a base section  222  which includes an outer profile that generally corresponds to the outer diameter of the body  26  of the case of  FIG. 9 . The chamber reamer  200  may also include a shoulder section  224 , a neck section  226 , a throat section  228 , and a bore section  230 . Each of these sections may generally correspond to the profile of the respective part of the chamber  80  of  FIG. 14C . 
     As shown in  FIG. 24 , the chamber reamer may include a minimum chamber length L c , a base-to-shoulder section length L BS , a neck section length L n , and a throat section length L tr . The chamber reamer  200  may further include a base diameter D base , a shoulder diameter D shoulder , a headspace diameter D HS , a neck diameter D n , a throat diameter D TR , and a pilot diameter D p . Also, the shoulder section  224  of the reamer  200  may form a shoulder angle γ and the section between the throat section  228  and the pilot section  230  may form a taper angle γ Table 5 (below) presents exemplary values for a finishing reamer for the chamber of  FIG. 14C . 
     The chamber reamers may be formed from high speed steel (e.g., HSS, M1, M2, M7, M50), cobalt alloys (e.g., M-35, M-42), tungsten carbide, and other suitable metal alloys. 
     
       
         
           
               
             
               
                 TABLE 5 
               
             
            
               
                   
               
               
                 Finishing Reamer Dimensions 
               
            
           
           
               
               
               
            
               
                 Description 
                 Parameter 
                 Value (a) 
               
               
                   
               
            
           
           
               
               
               
            
               
                 Minimum chamber length 
                 L c   
                 .7578 
               
               
                 Base to body-shoulder junction section length (b) 
                 L BS   
                 .4304 
               
               
                 Base to shoulder-neck junction section length (b) 
                 L HS   
                 .5278 
               
               
                 Neck section length 
                 L N   
                 .2300 
               
               
                 Throat section length 
                 L TR   
                 .0149 
               
               
                 Base diameter 
                 D Base   
                 .3765 
               
               
                 Shoulder diameter 
                 D shoulder   
                 .3717 
               
               
                 Headspace diameter 
                 D HS   
                 .2596 
               
               
                 Neck diameter 
                 D N   
                 .2510 
               
               
                 Throat diameter 
                 D TR   
                 .2320 
               
               
                 Pilot diameter 
                 D P   
                 .2180 
               
               
                 Shoulder angle 
                 γ 
                 29.8970° 
               
               
                 Taper angle 
                 δ 
                 2.5° 
               
               
                   
               
               
                 Notes: 
               
               
                 (a) Unless otherwise noted, unit dimensions measured in inches 
               
               
                 (b) Dimensions are to intersection of tangent lines 
               
            
           
         
       
     
     Preferably, a finishing reamer is sized to cut a chamber to the appropriate final dimensions, which are the correct size to meet specifications for a specific cartridge type. Sometimes, a roughing reamer may be used to make an initial cut in the work piece being chambered. Generally, roughing reamers may be used in production environments when a large number of chambers will need to be cut in an effort to avoid wear on the finishing reamer. The roughing reamer may be undersized with respect to the finishing reamer. For example, a roughing reamer may be approximately 0.002″ smaller (radially) overall than the finishing reamer. Additionally, the roughing reamer may be used to chamber sizing dies for the specific cartridge type that the finishing reamer is dimensioned for. Table 6 (below) presents exemplary values a roughing reamer for the chamber of  FIG. 14C . 
     
       
         
           
               
             
               
                 TABLE 6 
               
             
            
               
                   
               
               
                 Roughing Reamer Dimensions 
               
            
           
           
               
               
               
            
               
                 Description 
                 Parameter 
                 Value (a) 
               
               
                   
               
            
           
           
               
               
               
            
               
                 Minimum chamber length 
                 L c   
                 .7578 
               
               
                 Base to body-shoulder junction section length (b) 
                 L BS   
                 .4304 
               
               
                 Base to shoulder-neck junction section length (b) 
                 L HS   
                 .5278 
               
               
                 Neck section length 
                 L N   
                 .2300 
               
               
                 Throat section length 
                 L TR   
                 .0149 
               
               
                 Base diameter 
                 D Base   
                 .3745 
               
               
                 Shoulder diameter 
                 D shoulder   
                 .3697 
               
               
                 Headspace diameter 
                 D HS   
                 .2576 
               
               
                 Neck diameter 
                 D N   
                 .2490 
               
               
                 Throat diameter 
                 D TR   
                 .2300 
               
               
                 Pilot diameter 
                 D P   
                 .2180 
               
               
                 Shoulder angle 
                 γ 
                 29.8970° 
               
               
                 Taper angle 
                 δ 
                 2.5° 
               
               
                   
               
               
                 Notes: 
               
               
                 (a) Unless otherwise noted, unit dimensions measured in inches 
               
               
                 (b) Dimensions are to intersection of tangent lines 
               
            
           
         
       
     
       FIG. 26  presents an exemplary 5-station progressive press  252  for reshaping and reloading ammunition cases. The press  252  may include a handle  254 , shell plate  256 , cartridge catcher  258 , and five bushings  260 . A sizing die  262  may be received in one bushing  260 , and a powder die  264  that may include a powder measure  266  may be disposed in an adjacent bushing  260 . The press may also include a seating die  268  in another bushing  260 . 
     Referring to  FIG. 27 , the sizing die  262  may include a cylinder  270  having an upper end  272  and a lower end  274 . Additionally, the sizing die  262  may include a spindle adjust  276  and a spindle  278 . The lower end of the spindle  278  may further include an expander  280  and a decap pin  282 . The lower end  274  of the sizing die  262  may be configured and dimensioned to receive an intact but fired case  12 ′ of the ammunition cartridges of  FIG. 1, 10 or 11 . The fired case  12 ′ may include a spent primer  50 ′. The exterior surface of the sizing die  262  may include a collar portion  284 . The collar portion  284  may be located closer to the upper end  272  than to the lower end  274 . The exterior surface of the sizing die  262  below the collar portion may include a threaded segment  286 . A lock ring  288  having mating internal screw threads  290  may be secured to the threaded segment  286 . 
     Referring to  FIG. 28 , the cylinder  270  may include a central bore  292  that extends from the upper end  272  to the lower end  274 . The central bore  292  may be defined by an inner sidewall  294 . An upper portion  296  of the central bore may have greater diameter than a lower portion  298  of the central bore. An upper inner sidewall segment  300  may include internal screw threads  302 . An intermediate inner side wall segment  304  may include a tapered portion  306  that connects the upper inner side wall segment  300  to a lower inner side wall segment  308 . The lower inner side wall segment  308  may include a resizing segment  310 . The resizing segment  310  may be configured and dimensioned to correspond to the profile of the chamber  80  of  FIG. 14C . In use, the sizing die  262  may be pressed down on to a fired ammunition case  12 ′ that has been loaded on to the shell plate  256  of the reloading press  252 . The expander  280  may press the neck of the fired ammunition case  12 ′ against the resizing segment  310 . The resizing segment  310  may press the shoulder  30 ′ and body  26 ′ of the case  12 ′ into a pre-firing configuration  12  as generally shown in  FIG. 9A . The decap pin  282  may press the spent primer  50 ′ out of the primer pocket  48 ′. 
     Referring to  FIG. 29  and  FIG. 31 , the seating die  268  may include an elongated member  312  having an upper end  314  and a lower end  316 . The lower end  316  may include a telescoping seating stem  318 . The telescoping seating stem  318  may be configured and dimensioned to receive a reformed and loaded ammunition case  12  and bullet  68 . The lower exterior portion of the elongated member  312  may be threaded  320 . A lock ring  322  with mating internal threads  324  may be secured to the exterior screw threads  320 . The lock ring  322  may further include a wrench flat  326  and a locking mechanism  328  for fixing the position of the lock ring  322  to the elongated member  312 . 
     Referring to  FIG. 31  and  FIG. 32 , the seating die  268  may further include a floating bullet seating stem  330 , and a bullet seat adjustment screw  332 . The lower end of the telescoping seating stem  330  may include a bullet seating segment  334 . The bullet seating segment  334  may be configured and dimensioned to correspond to the profile of the chamber  80  of  FIG. 14C . The seating die  268  may be pressed down on a bullet  68  and a reformed case  12  that has been re-primed  50  and charged with propellant  60 . As shown in  FIG. 32 , the floating bullet seating sleeve  330  may position the bullet  68  at a desired and preset depth in the neck  28  of the case  12 , as the bullet seating segment  332  squeezes the neck  28  of the case  12  to securely retain the bullet  68 . 
       FIG. 33  shows a die storage box  334  for storing ammunition cartridge reloading dies (e.g.,  262 ,  268 ). The die storage box may be formed from cardboard, plastic, a polymer material or other suitable material. Other tools may be stored in the die storage box as well. For example, associated shell holders  336  and bushings  338  also may be stored in the die storage box  334 . As shown, in  FIG. 34 , the die storage box  334  may include receptacles for holding two ammunition cartridge reloading dies. In  FIG. 34 , one reloading die is the sizing die  262  of  FIGS. 26-28 , and the other reloading die is the seating die of  FIGS. 26, 29, 30, 31 and 32 . The die storage box  334 , the sizing die  262 , and the seating die  268  may be packaged as a kit  340 . 
     While it has been illustrated and described what at present are considered to be a preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made, and equivalents may be substituted for elements thereof without departing from the true scope of the invention. For example, the case may be used with other bullets, such as bullets with different configurations or nontraditional cores, as well as with different propellant. Also, different charges of propellant may be used. Additionally, features and/or elements from any embodiment may be used singly or in combination with other embodiments. Therefore, it is intended that this invention not be limited to the particular embodiments disclosed herein, but that the invention include all embodiments falling within the scope and the spirit of the present invention.