Firearm shell casing

Abstract

A dual use shell casing for use in a 9 mm firearm and for use in 9 mm magazines includes an upper portion, a lower portion, an internal cavity extending between the upper portion and the lower portion, the internal cavity configured to receive gunpowder and a projectile, and a tapered shoulder disposed at the upper portion and transitioning into a reduced diameter neck portion, the reduced diameter neck portion having an inner diameter equal to 0.313 inches. The tapered shoulder is configured to abut an internal shoulder within a barrel chamber of the 9 mm firearm.

What is claimed is: 
     
         1 . A dual use shell casing for use in a 9 mm firearm and for use in 9 mm magazines, the dual use shell casing comprising:
 an upper portion;   a lower portion;   an internal cavity extending between the upper portion and the lower portion, the internal cavity configured to receive gunpowder and a projectile; and   a tapered shoulder disposed at the upper portion and transitioning into a reduced diameter neck portion, the reduced diameter neck portion having an inner diameter equal to 0.313 inches, wherein the tapered shoulder is configured to abut an internal shoulder within a barrel chamber of the 9 mm firearm.   
     
     
         2 . The dual use shell casing of  claim 1 , wherein the tapered shoulder is configured to regulate a depth to which the dual use shell casing slides into the barrel chamber of the 9 mm firearm by abutting a barrel chamber seat within the barrel chamber of the 9 mm firearm while the reduced diameter neck portion extends into a bore of the barrel chamber. 
     
     
         3 . The dual use shell casing of  claim 2 , wherein the tapered shoulder defines an axial length, and the depth to which the dual use shell casing slides into the barrel chamber is determined based on the axial length of the tapered shoulder. 
     
     
         4 . The dual use shell casing of  claim 1 , further comprising a primer pocket, and a flash hole connecting the primer pocket to the internal cavity. 
     
     
         5 . The dual use shell casing of  claim 1 , wherein the tapered shoulder defines an acute angle relative to a central axis of the dual use shell casing. 
     
     
         6 . The dual use shell casing of  claim 1 , wherein a wall thickness of the lower portion is greater than a wall thickness of the upper portion. 
     
     
         7 . A dual use cartridge for use in a 9 mm firearm and for use in 9 mm magazines, the dual use cartridge comprising:
 a tapered shell casing comprising:
 an upper portion; 
 a lower portion; 
 an internal cavity extending between the upper portion and the lower portion, the internal cavity configured to receive gunpowder and a projectile; and 
 a tapered shoulder disposed at the upper portion and transitioning into a reduced diameter neck portion, the reduced diameter neck portion having an inner diameter equal to 0.313 inches, 
   a projectile disposed within the internal cavity at the reduced diameter neck portion and secured therein; and   gunpowder disposed within the internal cavity below the projectile, wherein the tapered shoulder is configured to abut an internal shoulder within a barrel chamber of the 9 mm firearm.   
     
     
         8 . The dual use cartridge of  claim 7 , wherein the tapered shoulder is configured to regulate a depth to which the tapered shell casing slides into the barrel chamber of the 9 mm firearm by abutting a barrel chamber seat within the barrel chamber of the 9 mm firearm while the reduced diameter neck portion extends into a bore of the barrel chamber. 
     
     
         9 . The dual use cartridge of  claim 8 , wherein the tapered shoulder defines an axial length, and the depth to which the shell casing slides into the barrel chamber is determined based on the axial length of the tapered shoulder. 
     
     
         10 . The dual use cartridge of  claim 7 , wherein the lower portion defines a primer pocket. 
     
     
         11 . The dual use cartridge of  claim 10 , further comprising primer compound disposed in the primer pocket. 
     
     
         12 . The dual use cartridge of  claim 11 , further comprising a primer cup configured to seal the primer compound in the primer pocket. 
     
     
         13 . The dual use cartridge of  claim 7 , wherein the lower portion includes a shell casing rim. 
     
     
         14 . The dual use cartridge of  claim 7 , wherein the gunpowder and the projectile define a gap therebetween. 
     
     
         15 . The dual use cartridge of  claim 7 , wherein the tapered shoulder defines an acute angle relative to a central axis of the shell casing. 
     
     
         16 . The dual use cartridge of  claim 7 , wherein a diameter of the projectile is smaller than a diameter of the lower portion. 
     
     
         17 . The dual use cartridge of  claim 7 , wherein a wall thickness of the lower portion is greater than a wall thickness of the upper portion. 
     
     
         18 . A dual use cartridge configured for use with a 9 mm firearm and for use in 9 mm magazines, the dual use cartridge comprising:
 a tapered shell casing comprising an upper portion, a lower portion, an internal cavity extending between the upper portion and the lower portion and configured to receive gunpowder and a projectile, a tapered shoulder disposed at the upper portion and transitioning to a reduced diameter neck portion, a primer pocket, and a flash hole connecting the primer pocket to the internal cavity;   a projectile disposed within the internal cavity at the reduced diameter neck portion and secured therein;   gunpowder disposed within the internal cavity below the projectile;   a primer compound disposed in the primer pocket; and   a primer cup configured to seal the primer compound in the primer pocket,   wherein the reduced diameter neck portion has an inner diameter equal to 0.313 inches, and   wherein the tapered shell casing shoulder is configured to abut an internal shoulder within a barrel chamber of the 9 mm firearm.   
     
     
         19 . The dual use cartridge of  claim 18 , wherein the tapered shoulder is configured to regulate a depth to which the tapered shell casing slides into the barrel chamber of the 9 mm firearm by abutting a barrel chamber seat within the barrel chamber of the 9 mm firearm while the reduced diameter neck portion extends into a bore of the barrel chamber. 
     
     
         20 . The dual use cartridge of  claim 19 , wherein the tapered shoulder defines an axial length, and the depth to which the shell casing slides into the barrel chamber is determined based on the axial length of the tapered shoulder.