Ammunition blank and corresponding bolt

Abstract

An ammunition cartridge casing has a casing base with a proximal end surface, a casing body defining an inside volume, and a distal end portion. The casing base defines a primer pocket in communication with the inside volume of the casing body, where the primer pocket is sized and configured such that when a primer is installed in the primer pocket, a proximal face of the primer is recessed into the base at least 0.010″ with respect to the end surface. Blank ammunition made with the cartridge casing is configured for use with a rifle having a bolt with a boss on the breech face that corresponds to the recessed primer.

1 . A cartridge casing comprising:
 a base having an end surface and defining a centrally located primer pocket, wherein the base has an axially recessed annular region extending radially outward from the primer pocket, the axially recessed annular region recessed axially with respect to the end surface by at least 0.014″; and   a casing body extending along a central axis from the base to a mouth and defining an inside volume;   wherein the primer pocket is sized such that when a primer is installed in the primer pocket that a proximal face of the primer is flush with or recessed axially with respect to the axially recessed annular region.   
     
     
         2 . The cartridge casing of  claim 1 , further comprising the primer installed in the primer pocket. 
     
     
         3 . The cartridge casing of  claim 1 , wherein the casing body includes a proximal portion and distal end portion of smaller diameter than the proximal portion, wherein the casing body further defines a taper between the proximal portion and the distal end portion. 
     
     
         4 . The cartridge casing of  claim 1 , wherein the mouth of the cartridge is sized for a projectile having a diameter of 7.62 mm, 6.5 mm, 6.8 mm, or 5.56 mm. 
     
     
         5 . A blank firearms ammunition cartridge comprising:
 the cartridge casing of  claim 1 ;   the primer installed in the primer pocket;   a projectile retained in the mouth of the cartridge casing; and   a quantity of propellant in the inside volume of the cartridge casing.   
     
     
         6 . The blank firearms ammunition cartridge of  claim 5 , wherein the cartridge is configured for use with a firearm chambered for 7.62×51 mm, 6.8×51 mm, 6.5 Creedmoor, or 5.56×45 mm NATO. 
     
     
         7 . The blank firearms ammunition cartridge of  claim 5 , wherein the cartridge is configured for use in a handgun. 
     
     
         8 . A bolt for a firearm, the bolt comprising:
 a bolt body extending along a central axis to a distal end, the bolt body defining a firing pin bore, wherein the distal end includes a breech face sized and configured to engage a cartridge head;   a protrusion on the breech face, the protrusion extending axially from the breech face by at least 0.014″, wherein the protrusion is configured to be at least partially received in the cartridge head, and wherein the firing pin bore extends through a distal surface of the protrusion.   
     
     
         9 . The bolt of  claim 8 , wherein the protrusion extends axially by at least 0.020″ from the breech face. 
     
     
         10 . The bolt of  claim 8 , further defining a transverse bore. 
     
     
         11 . The bolt of  claim 8 , wherein the breech face defines an ejector pin opening and the bolt further comprising an ejector pin biased to extend through the ejector pin opening. 
     
     
         12 . The bolt of  claim 11 , wherein the ejector pin opening intersects the protrusion. 
     
     
         13 . The bolt of  claim 8 , further comprising lugs interspersed circumferentially around the breech face on the distal end of the bolt body, each of the lugs extending axially and protruding radially from the bolt body. 
     
     
         14 . The bolt of  claim 13 , further comprising an extractor pivotably attached to the bolt body and movable between a resting state and a deflected state, the extractor including an extractor hook extending radially inward and an extractor lug extending radially outward, wherein in the deflected state the extractor lug extends radially outward from the central axis a distance that is greater than a radial dimension from the central axis of neighboring lugs. 
     
     
         15 . A firearm including the bolt of  claim 8 . 
     
     
         16 . In combination, a blank ammunition cartridge and a bolt for an autoloading firearm, the combination comprising:
 a blank ammunition cartridge comprising:
 a cartridge casing having a base having an end surface and defining a centrally located primer pocket, and having a casing body extending along a central axis from the base to a mouth and defining an inside volume, wherein the base has an axially recessed annular region extending radially outward from the primer pocket, the axially recessed annular region recessed axially with respect to the end surface by at least 0.014″; 
 a primer installed in the primer pocket such that a proximal face of the primer is flush with or recessed axially with respect to the axially recessed annular region; 
 a projectile retained in the mouth of the cartridge casing; and 
 a quantity of propellant in the inside volume of the cartridge casing; and 
   a bolt comprising:
 a bolt body extending along a central axis to a distal end, the bolt body defining a firing pin bore, wherein the distal end includes a breech face sized and configured to engage a cartridge head; and 
 a protrusion on the breech face, the protrusion extending axially from the breech face by a recess distance of at least 0.014″, wherein the protrusion is configured to be at least partially received in the cartridge head, and wherein the firing pin bore extends through a distal surface of the protrusion. 
   
     
     
         17 . The combination of  claim 16 , wherein the recess distance is at least 0.020″. 
     
     
         18 . The combination of  claim 16 , comprising:
 lugs interspersed circumferentially around the breech face on the distal end of the bolt body, each of the lugs extending axially and protruding radially from the bolt body;   a boss on the breech face, the boss extending axially from the breech face by the recess distance ±0.001″   wherein the firing pin bore extends through a distal surface of the boss; and   an extractor pivotably attached to the bolt body and movable between a resting state and a deflected state, the extractor including an extractor hook extending radially inward and an extractor lug extending radially outward, wherein in the deflected state the extractor lug extends radially outward from the central axis a distance that is greater than a radial dimension from the central axis of neighboring lugs.   
     
     
         19 . The combination of  claim 18 , wherein the breech face defines an ejector pin opening that intersects the boss, and the bolt comprises at least one ejector pin biased to extend through the ejector pin opening. 
     
     
         20 . A firearm comprising the combination of  claim 16 .