Frangible bullet

Abstract

A frangible hollow point bullet is disclosed. The bullet (or slug) is formed from a frangible material such as sintered copper to provide a bullet-shaped body. A plurality of coaxial, substantially cylindrical cavities having progressively decreasing bore diameters are formed in the nose of the bullet-shaped body, extending rearwardly therefrom, to provide a bullet that both expands and fragments in a semicontrolled fashion upon impact with a target. In a preferred embodiment, at least one of the coaxial cavities is multiply scored to provide a substantially symmetric fragmentation pattern and a controlled and uniform fragment size. Controlling the aggregate depth of the coaxial cavities enables the retention of a recoverable base or shank that is suitable for ballistic investigation following bullet impact. Bullets and slugs, made in accordance with the present invention, have standard calibers and, when incorporated into conventional cartridges and shotgun shell casings respectively, may be fired at subsonic, sonic or supersonic velocities by conventional weapons.

What we claim is:  
     
         1 . A substantially bullet-shaped projectile comprising a body having a leading end, a trailing end and a frangible body portion therebetween, and a plurality of cavities having cylindrical walls extending rearwardly into said body portion from said leading end, the diameter of said cylindrical walls of each cavity comprising said plurality of cavities being progressively smaller in a direction rearward of said leading end.  
     
     
         2 . The projectile in accordance with  claim 1  further comprising a plurality of grooves on said cylindrical wall of at least one of said plurality of cavities.  
     
     
         3 . The projectile of  claim 1  wherein said projectile is a bullet.  
     
     
         4 . The projectile of  claim 2  wherein said projectile is a bullet.  
     
     
         5 . The projectile in accordance with  claim 1  further comprising a plurality of grooves on said cylindrical wall of each cavity comprising said plurality of cavities.  
     
     
         6 . The projectile of  claim 5  wherein said projectile is a bullet.  
     
     
         7 . A projectile in accordance with  claim 1  wherein said body portion has a smooth outer surface.  
     
     
         8 . A projectile in accordance with  claim 2  wherein said body portion has a smooth outer surface.  
     
     
         9 . A substantially bullet-shaped projectile having a leading end, a trailing end and a frangible body portion therebetween, and a hollow cavity in said leading end of said body portion, said hollow cavity comprising a plurality of coaxial cylindrical cavities extending rearwardly into said body portion from said leading end, the diameter of each cylindrical cavity comprising said plurality of cavities decreasing stepwise in discrete increments in a direction rearward of said leading end.  
     
     
         10 . A projectile in accordance with  claim 9  wherein at least one said cylindrical cavity comprising said hollow cavity has a cavity wall bearing stress risers thereon.  
     
     
         11 . A cartridge comprising a projectile in accordance with  claim 9 .  
     
     
         12 . A cartridge comprising a projectile in accordance with  claim 10 .  
     
     
         13 . A substantially bullet-shaped projectile having a leading end, a trailing end and a frangible body portion therebetween, and a hollow cavity in said leading end of said body portion, said hollow cavity comprising a plurality of coaxial conical cavities extending rearwardly into said body portion from said leading end, the diameter of each conical cavity comprising said plurality of cavities decreasing stepwise in discrete increments in a direction rearward of said leading end.  
     
     
         14 . A projectile in accordance with  claim 13  wherein at least one said conical cavity comprising said hollow cavity has a cavity wall bearing stress risers thereon.  
     
     
         15 . A cartridge comprising a projectile in accordance with  claim 13 .  
     
     
         16 . A cartridge comprising a projectile in accordance with  claim 14 .  
     
     
         17 . A shotgun shell comprising a plurality of pellets wherein each pellet comprising said plurality of pellets has an exterior surface with a plurality of cavities thereon.  
     
     
         18 . A shotgun shell comprising a plurality of pellets embedded within a foam or a gel.  
     
     
         19 . A shotgun shell comprising a projectile having a leading end and a trailing end wherein said trailing end has a plurality of fins attached thereto.