Firearm cartridge

Abstract

The firearm cartridge has an upper chamber adapted to house gunpowder and a bullet, a lower pocket adapted to house a primer, and a flash hole extending there between. The lower pocket has a ledge disposed generally perpendicularly to the flash hole. The flash hole is formed with a perimeter wall that has a convex curvature adjacent to the ledge of the primer pocket. The convex curvature of the flash hole perimeter wall can either be a continuous curve, or can be approximated by a series of smaller facets, as might be produced in various manufacturing processes.

1 - 6 . (canceled) 
     
     
         7 . A firearm cartridge case comprising:
 an upper chamber adapted to house gunpowder and a bullet, said upper chamber having a lower ledge,   a lower pocket adapted to house a primer, said lower pocket having an upper ledge, and   a flash hole extending between said upper chamber and said lower pocket and being defined by a perimeter wall, said flash hole perimeter wall having a convex curvature and extending from said lower ledge of said upper chamber to said upper ledge of said lower pocket,   said flash hole having a lowermost diameter adjacent said upper ledge of said lower pocket and having an uppermost diameter adjacent said lower ledge of said upper chamber,   wherein said lowermost diameter is larger than said uppermost diameter, and wherein a diameter of said flash hole between said lowermost and uppermost diameters only decreases from said lowermost diameter to said uppermost diameter,   wherein the convex curvature of said perimeter wall is approximated through a plurality of shaped cuts.   
     
     
         8 . The firearm cartridge case of  claim 7 , wherein the convex curvature of said flash hole perimeter wall is a mathematically derived shape. 
     
     
         9 . The firearm cartridge case of  claim 8 , wherein the mathematically derived shape of said flash hole perimeter wall is selected from a group consisting of arcuate, parabolic, elliptical, Von Karmen, Haack, power series, and splined. 
     
     
         10 . The firearm cartridge case of  claim 7 , wherein said case is formed from a single, unitary, monolithic piece of metal. 
     
     
         11 . The firearm cartridge case of  claim 10 , wherein said metal is brass. 
     
     
         12 . The firearm cartridge case of  claim 10 , wherein said metal is steel. 
     
     
         13 . The firearm cartridge case of  claim 7 , wherein said lower ledge of said upper chamber is disposed generally perpendicularly to a longitudinal axis of said firearm cartridge case, and wherein said flash hole perimeter wall extends from a radially inner edge of said lower ledge of said upper chamber to said upper ledge of said lower pocket. 
     
     
         14 . The firearm cartridge case of  claim 7 , wherein said upper ledge of said lower pocket is disposed generally perpendicularly to a longitudinal axis of said firearm cartridge case, and wherein said flash hole perimeter wall extends from said lower ledge of said upper chamber to a radially inner edge of said upper ledge of said lower pocket. 
     
     
         15 . The firearm cartridge case of  claim 7 , wherein said lower ledge of said upper chamber is disposed generally perpendicularly to a longitudinal axis of said firearm cartridge case, wherein said upper ledge of said lower pocket is disposed generally perpendicularly to the longitudinal axis of said firearm cartridge case, and wherein said flash hole perimeter wall extends from a radially inner edge of said lower ledge of said upper chamber to a radially inner edge of said upper ledge of said lower pocket. 
     
     
         16 . The firearm cartridge case of  claim 7  wherein said shaped cuts are step shaped cuts. 
     
     
         17 . The firearm cartridge case of  claim 7  wherein said shaped cuts are scallop shaped cuts. 
     
     
         18 . The firearm cartridge case of  claim 7  wherein said shaped cuts are concentric conic facets.