Small arms cartridge

Abstract

Provided is a centerfire rifle cartridge. A case has a head end, an open mouth end for receiving a projectile, and a central axis. The head end has a base portion substantially conforming to that of a .50 BMG cartridge. The case has a case wall with a taper of up to 1.0° relative to the central axis. A frusto-conical shoulder portion extends from the case wall and has an angle of approximately 40° relative to the central axis. A neck portion extends from the shoulder portion and has a mouth sized to receive a .375 caliber (9.5 mm) projectile.

1 . A centerfire rifle cartridge, comprising:
 a case having a head end, an open mouth end for receiving a projectile, a central axis, and an axial length measured along the central axis, the head end having a base portion up to 0.804 inches in diameter;   the case having a case wall, the case wall having a taper of 0.85° to 1.0° relative to the central axis, a frusto-conical shoulder portion extending from the case wall and having an angle of 35° to 45° relative to the central axis, and a neck portion extending from the shoulder portion; and   the neck portion having a mouth sized to receive a .375 caliber projectile.   
     
     
         2 . The cartridge of  claim 1 , wherein the case has a total axial length in the range of about 3.24 inches to about 3.29 inches. 
     
     
         3 . The cartridge of  claim 1 , wherein the wall has an axial length from the head end of about 2.50 inches. 
     
     
         4 . The cartridge of  claim 1 , wherein the case wall taper is about 0.9° relative to the central axis. 
     
     
         5 . The cartridge of  claim 1 , wherein the case capacity is greater than 200 grains H 2 O. 
     
     
         6 . The cartridge of  claim 5 , wherein the case has a capacity in the range of about 210-230 grains H 2 O. 
     
     
         7 . The cartridge of  claim 1 , further comprising a projectile having a weight in the range of about 350-410 grains 
     
     
         8 . The cartridge of  claim 7 , wherein the loaded overall length is at least 4.65 inches. 
     
     
         9 . The cartridge of  claim 8 , wherein the loaded overall length is about 4.825 inches.