Subsonic and reduced velocity ammunition cartridges

Abstract

Subsonic and reduced velocity rifle ammunition cartridges are disclosed. The ammunition cartridges can be fired through a standard rifle with a common twist rate at subsonic and reduced velocities. The subsonic ammunition uses propellant that is not typically used with the selected rifle cartridge. Cycling subsonic ammunition cycles the firing and loading mechanisms of fully automatic and semiautomatic weapons. Cycling subsonic ammunition cartridges contain slow burning propellant, such as cannon powder, and a heavy projectile with a long bearing surface. Non-cycling subsonic ammunition uses moderately fast burning pistol propellant. The projectiles are carefully selected to be stable at subsonic or reduced velocities and at the standard rifle twist rate for given cartridge caliber.

1 . A subsonic or reduced velocity ammunition cartridge comprising: 
 a standard rifle cartridge casing having a base end and an open end, sized to be used with a standard rifle having a standard rifle twist rate, said cartridge casing having an internal volume;    a primer inserted in the base end of the casing;    a quantity of propellant disposed within the casing, wherein the propellant is not a standard rifle propellant; and    a projectile sized to fit within the open end of the casing and which is stable at subsonic velocity and at the rifle twist rate.    
     
     
         2 . The cartridge of  claim 1 , wherein the projectile is selected to have a center of mass that is approximately equal to the center of length.  
     
     
         3 . The cartridge of  claim 1 , wherein the propellant is a moderately fast burn rate pistol propellant.  
     
     
         4 . The cartridge of  claim 3 , wherein the quantity of propellant is in the range from about 15 to 20%, by weight, of the propellant used in a standard supersonic rifle cartridge using the cartridge casing.  
     
     
         5 . The cartridge of  claim 1 , wherein the propellant is spherical powder.  
     
     
         6 . The cartridge of  claim 1 , wherein the cartridge casing is colored to identify the cartridge as a subsonic ammunition cartridge.  
     
     
         7 . The cartridge of  claim 6 , wherein the cartridge casing is colored black.  
     
     
         8 . The cartridge of  claim 1 , wherein the projectile, when fired from the rifle, travels at subsonic or reduced velocity that stabilizes and maintains sufficient energy to be lethal and penetrate modern body armor.  
     
     
         9 . The cartridge of  claim 1 , wherein the cartridge may be used with a rifle equipped with a sound suppressor.  
     
     
         10 . The cartridge of  claim 1 , wherein the projectile, when fired from the rifle, travels at subsonic or reduced velocity that stabilizes and follows a predictable trajectory.  
     
     
         11 . The cartridge of  claim 1 , wherein the projectile, when fired from the rifle, travels at subsonic or reduced velocity that stabilizes and follows a predictable trajectory at a range up to about 200-800 yards depending on caliber.  
     
     
         12 . The cartridge of  claim 1 , wherein the projectile, when fired from the rifle, travels at subsonic or reduced velocity that stabilizes and achieves Minute of Angle at 100 yards.  
     
     
         13 . The cartridge of  claim 1 , wherein the rifle is an automatic or semiautomatic rifle having a cycling firing mechanism, wherein the projectile travels as subsonic or reduced velocity when fired from the rifle, and wherein the cartridge produces sufficient pressure to cycle the firing mechanism.  
     
     
         14 . The cartridge of  claim 13 , wherein the projectile is heavier than a comparable projectile designed for supersonic flight for use with the rifle cartridge casing.  
     
     
         15 . The cartridge of  claim 13 , wherein the projectile has a longer bearing surface than a comparable projectile designed for supersonic flight and use with the rifle cartridge casing.  
     
     
         16 . The cartridge of  claim 13 , wherein the propellant is cannon propellant.  
     
     
         17 . The cartridge of  claim 1 , wherein the rifle cartridge is a .223 caliber cartridge containing from 3.5 to 4.5 grains of pistol propellant and a projectile weighing from 50 to 60 grains.  
     
     
         18 . The cartridge of  claim 1 , wherein the rifle cartridge is a .308 caliber cartridge containing from 6 to 9 grains of pistol propellant and a projectile weighing from 150 to 220 grains.  
     
     
         19 . The cartridge of  claim 1 , wherein the rifle cartridge is a .50 BMG cartridge containing from 20 to 60 grains of pistol propellant and a projectile weighing from 525 to 900 grains.  
     
     
         20 . The cartridge of  claim 1 , wherein the rifle cartridge is a .300 Winchester Magnum cartridge containing from 8 to 16 grains of pistol propellant and a projectile weighing from 150 to 230 grains.  
     
     
         21 . The cartridge of  claim 1 , wherein the rifle cartridge is a 7.62×39mm cartridge containing from 7.5 to 8.5 grains of pistol propellant and a projectile weighing from 170 to 190 grains.  
     
     
         22 . The cartridge of  claim 13 , wherein the rifle cartridge is a .223 caliber cartridge containing from 18 to 25 grains of cannon propellant and a projectile weighing from 90 to 125 grains.  
     
     
         23 . The cartridge of  claim 22 , wherein the projectile has a bearing surface ranging from 0.4 to 1.1 inches.  
     
     
         24 . The cartridge of  claim 22 , wherein the projectile has a bearing surface ranging from 0.8 to 0.9 inches.  
     
     
         25 . A method of making a subsonic or reduced velocity ammunition cartridge comprising: 
 obtaining a standard rifle cartridge casing having a base end and an open end, sized to be used with a standard rifle having a standard rifle twist rate, said cartridge casing having an internal volume, wherein a primer is inserted in the base end of the casing;    selecting a projectile sized to fit within the open end of the casing which is stable at subsonic or reduced velocity and at the standard rifle twist rate;    selecting a moderately fast burning pistol propellant;    disposing a quantity of the propellant within the casing, wherein the quantity of propellant is selected to leave substantial void space within the casing internal volume and to generate sufficient pressure upon ignition to expel the projectile at subsonic or reduced velocity; and    disposing the projectile within the open end of the casing.    
     
     
         26 . A method of making a subsonic or reduced velocity ammunition cartridge that can cycle the firing and loading action of an automatic or semiautomatic rifle, comprising: 
 obtaining a standard rifle cartridge casing having a base end and an open end, sized to be used with a standard automatic or semiautomatic rifle having a standard rifle twist rate, said cartridge casing having an internal volume, wherein a primer is inserted in the base end of the casing;    selecting a projectile sized to fit within the open end of the casing which is stable at subsonic or reduced velocity and at the standard rifle twist rate, wherein the projectile is heavier and has a longer bearing surface than a comparable projectile designed for supersonic flight for use with the rifle cartridge casing;    selecting a slow burning cannon propellant;    disposing a quantity of the propellant within the casing, wherein the quantity of propellant is selected to generate sufficient pressure upon ignition to expel the projectile at subsonic or reduced velocity and to cycle the firing and loading action; and    disposing the projectile within the open end of the casing.