Lead free, composite polymer based bullet and cartridge case, and method of manufacturing

Abstract

A lead-free, composite polymer based bullet and cartridge case, wherein the cartridge case is formed by matingly engaging a cylindrical body and a corresponding base. A belted cartridge case has a double wall design, which provides the cartridge with increased thickness, and in turn, a reinforced structure useful for withstanding breakage from an impact caused by high pressure loads. The belt is formed to have an inner diameter at a first end of the base that is larger than the outer diameter of any portion of the cylindrical body. A nested cartridge case allows the second end of the case to nest in a first end of the base at an engaging region.

1 . A lead-free cartridge case capable of holding a bullet, the bullet having a cannelure formed along an outer circumferential surface of a body of the bullet, the cartridge case comprising: 
 a cylindrical body having a first end and a second end opposite the first end; and    a base having an axially extending wall at a first end of the base, wherein an inner diameter of the axially extending wall of the base is greater than an outer diameter of the second end of the cylindrical body, and wherein the axially extending wall of the base engages an engaging region of the cylindrical body, forming a belted portion.    
   
   
       2 . The cartridge case according to  claim 1 , wherein the belted portion of the case is defined by a double wall structure.  
   
   
       3 . The cartridge case according to  claim 2 , wherein the base and the cylindrical body engage each other by any one of friction, snap fitting, welding, and gluing.  
   
   
       4 . The cartridge case according to  claim 1 , wherein the cylindrical body comprises: 
 a plurality of wall portions extending substantially axially to form a cylindrical shape and define a bullet holding chamber intermediate the first and second ends of the cylindrical body and a mouth at the first end of the cylindrical body.    
   
   
       5 . The cartridge case according to  claim 4 , wherein the plurality of wall portions taper in a direction from the second end to the first end of the cylindrical body, wherein the diameter at the second end of the cylindrical body is greater than the diameter at the first end of the cylindrical body.  
   
   
       6 . The cartridge case according to  claim 5 , wherein the tapering plurality of wall portions define a neck region disposed intermediate the holding chamber and the mouth.  
   
   
       7 . The cartridge case according to  claim 4 , further comprising at least one lip lock extending radially inward from an inner surface of the wall portions, wherein the at least one lip lock is configured to have a shape that is one of symmetrical, asymmetrical, trapezoidal, triangular, rectangular, sinusoidal, toothed, and zig zag.  
   
   
       8 . The cartridge case according to  claim 1 , wherein the base further comprises: 
 a rim disposed at and extending radially away from a second end of the base, which is opposite the first end;    a circumferential groove formed in the outer surface of the base and disposed intermediate the rim and the axially extending wall;    a web portion disposed intermediate the groove and the axially extending wall, the web portion separating a primer holding chamber from the axially extending wall; and    a central opening extending from the second end to the first end of the base and defining a radial edge of the primer holding chamber.    
   
   
       9 . The cartridge case according to  claim 8 , wherein a first end of the central opening includes the radial edge, which communicates with the primer holding chamber of the base and the bullet holding chamber of the cylindrical body.  
   
   
       10 . The cartridge case according to  claim 9 , wherein an outer diameter of the rim is greater than an outer diameter of the groove and equal to or less than an outer diameter of the axially extending wall.  
   
   
       11 . The cartridge case according to  claim 10 , wherein the outer diameter of the groove is less than the outer diameter of the axially extending wall.  
   
   
       12 . The cartridge case according to  claim 1 , wherein the cartridge case is manufactured from a composite polymer.  
   
   
       13 . The cartridge case according to  claim 12 , wherein the composite polymer includes at least one of nylon  6 / 6 , nylon  6 , and glass fibers.  
   
   
       14 . The cartridge case according to  claim 12 , wherein the composite polymer includes additives.  
   
   
       15 . The cartridge case according to  claim 12 , wherein the composite polymer includes stabilizers.  
   
   
       16 . A base for a lead-free cartridge case having a cylindrical body for holding a bullet, the base comprising: 
 an axially extending wall at a first end of the base, wherein the cylindrical body of the cartridge case forms an interference fit with an inner diameter of the axially extending wall.    
   
   
       17 . A base according to  claim 16 , further comprising: 
 a rim disposed at and extending radially away from a second end of the base, which is opposite the first end;    a circumferential groove formed in an outer surface of the base and disposed intermediate the rim and the axially extending wall;    a web portion disposed intermediate the groove and the axially extending wall, the web portion separating a primer holding chamber from the axially extending wall; and    a central opening extending from the second end to the first end of the base and defining a radial edge of the primer holding chamber.    
   
   
       18 . A lead-free cartridge case capable of holding a bullet, the bullet having a cannelure formed along an outer circumferential surface of a body of the bullet, the cartridge case comprising: 
 a cylindrical body having a first end and a second end opposite the first end; and    a base having an axially extending wall, wherein the cylindrical body forms an interference fit with an inner surface of the axially extending wall.    
   
   
       19 . A lead-free cartridge case capable of holding a bullet, the bullet having a cannelure formed along an outer circumferential surface of a body of the bullet, the cartridge case comprising: 
 a cylindrical body having a first end and a second end opposite the first end, wherein second end of the cylindrical body comprises an axially extending wall; and    a base having an axially extending wall at a first end of the base, wherein an inner diameter of the axially extending wall at the first end of the base is greater than an outer diameter of the axially extending wall at the second end of the cylindrical body, and wherein the axially extending wall of the base and the axially extending wall of the second end of the cylindrical body, respectively, engage each other to define a nested engaging portion.    
   
   
       20 . The cartridge case according to  claim 19 , wherein the base and the cylindrical body engage each other by any one of friction, snap fitting, welding, and gluing.  
   
   
       21 . The cartridge case according to  claim 19 , wherein the cylindrical body comprises: 
 a plurality of wall portions extending substantially axially to form a cylindrical shape and define a bullet holding chamber intermediate the first and second ends of the cylindrical body and a mouth disposed at the first end of the cylindrical body.    
   
   
       22 . The cartridge case according to  claim 21 , wherein a combined thickness of the axially extending wall of the base and the axially extending wall of the cylindrical body is substantially equal to a thickness of the wall portions of the cylindrical body at a location intermediate the first and second ends of the cylindrical body.  
   
   
       23 . The cartridge case according to  claim 21 , wherein the outer diameter of the axially extending wall at the second end of the cylindrical body is less than an outer diameter of bullet holding chamber of the cylindrical body.  
   
   
       24 . The cartridge case according to  claim 22 , wherein the plurality of wall portions taper in a direction from the second end to the first end of the cylindrical body.  
   
   
       25 . The cartridge case according to  claim 24 , wherein the tapering plurality of wall portions define a neck region disposed intermediate the holding chamber and the mouth.  
   
   
       26 . The cartridge case according to  claim 21 , further comprising at least one lip lock extending radially inward from an inner surface of the wall portions, wherein the at least one lip lock is configured to have a shape that is one of symmetrical, asymmetrical, trapezoidal, triangular, rectangular, sinusoidal, toothed, and zig zag.  
   
   
       27 . The cartridge case according to  claim 19 , wherein the base further comprises: 
 a rim disposed at and extending radially away from a second end of the base, which is opposite the first end;    a circumferential groove formed in the outer surface of the base and disposed intermediate the rim and the axially extending wall;    a web portion disposed intermediate the groove and the axially extending wall, the web portion separating a primer holding chamber from the axially extending wall; and    a central opening extending from the second end to the first end of the base and defining a radial edge of the primer holding chamber.    
   
   
       28 . The cartridge case according to  claim 27 , wherein the central opening includes the radial edge, which communicates with the primer holding chamber of the base and the bullet holding chamber of cylindrical body.  
   
   
       29 . The cartridge case according to  claim 28 , wherein an outer diameter of the rim is greater than can outer diameter of the groove and equal to or less than an outer diameter of the axially extending wall.  
   
   
       30 . The cartridge case according to  claim 29 , wherein the outer diameter of the groove is less than the outer diameter of the axially extending wall.  
   
   
       31 . The cartridge case according to  claim 19 , wherein the cartridge case is manufactured from a composite polymer.  
   
   
       32 . The cartridge case according to  claim 31 , wherein the composite polymer includes at least one of nylon 6/6, nylon 6, and glass fibers.  
   
   
       33 . The cartridge case according to  claim 31 , wherein the composite polymer includes additives.  
   
   
       34 . The cartridge case according to  claim 31 , wherein the composite polymer includes stabilizers.  
   
   
       35 . The cartridge case according to  claim 19 , wherein an outer diameter of the axially extending wall of the base is equal to an outer diameter of the second end of the cylindrical body.  
   
   
       36 . The cartridge case according to  claim 19 , wherein the axially extending wall of the base and the axially extending wall of the body have a corresponding engaging shape that is one of toothed, sinusoidal, rectangular, triangular, and trapezoidal.