Bullet jacket and method for the manufacture thereof

Abstract

A bullet jacket, and method of making a bullet jacket are disclosed, wherein bullets placed therein will, when fired, expand at low velocities, while maintaining high weight retention at higher velocities. The bullet jacket is preferably made of a copper based material, and comprises a solid base portion and an upper end portion defining a cavity therein, in which a bullet core material is located. The walls of the cavity decrease in width away from the base and curve inwardly to form an ogive shape. The length of the cavity section of the bullet jacket is between 58 to 61 percent of the total length of the bullet jacket, and the total weight of the solid base portion of the bullet jacket is between 48 to 52 percent of the total weight of the bullet jacket. The bullet core is made by using conventional means to seat and enclose the bullet core within the bullet jacket of the present invention. In manufacturing the bullet jacket, the jacket mouth or lip thickness is made to be between 0.025 to 0.060 of an inch. Four to 6 cuts are used to cut the jacket lip to a minimum depth of 0.015 inch to a maximum depth of 0.450 inch.

1 . A bullet jacket formed from a jacket material, the jacket comprising a solid base portion and an axially opposite end portion having an outer lip at an upper edge thereof, said end portion defining a cavity in the bullet jacket wherein said cavity has an opening in a direction towards the end portion and a length which comprises 45 to 70 percent of the total length of the bullet jacket.  
   
   
       2 . The bullet jacket according to  claim 1 , wherein the length of the cavity comprises 58 to 61 percent of the total length of the bullet jacket.  
   
   
       3 . The bullet jacket according to  claim 1 , wherein the outer lip has a uniform thickness, and the bullet jacket increases in hardness and strength from the upper edge of the lip to the base portion of the bullet jacket.  
   
   
       4 . The bullet jacket according to  claim 1  wherein the jacket material is selected from the group consisting of copper, alloys of copper, aluminum, alloys of aluminum, iron, steel, and combinations thereof.  
   
   
       5 . The bullet jacket according to  claim 4 , wherein the jacket material is copper.  
   
   
       6 . The bullet jacket according to  claim 1 , wherein a weighted core material is positioned in the cavity.  
   
   
       7 . The bullet jacket according to  claim 6 , wherein the weighted core material is selected from the group consisting of lead, alloys of lead, tin, alloys of tin, zinc, antimony, metal particles and rubber matrix, metal particles and polymer material, and any other material having a specific gravity greater than 0.5 grams per cubic centimeters.  
   
   
       8 . The bullet jacket according to  claim 6 , wherein the weighted core material is bonded to walls of the cavity using heat or an adhesive.  
   
   
       9 . The bullet jacket according to  claim 1 , wherein the solid base portion has a weight ranging from approximately 48 percent to 52 percent of a total weight of the bullet jacket.  
   
   
       10 . The bullet jacket according to  claim 1 , wherein the outer lip has a thickness ranging from approximately 0.025 of an inch to 0.06 of an inch, and a ratio of the outer lip thickness to a bottom cavity wall thickness is between 0.21 to 0.295.  
   
   
       11 . The bullet jacket according to  claim 1 , wherein the solid base portion has a boat-tail base design or a flat-base design.  
   
   
       12 . The bullet jacket according to  claim 1 , wherein the outer lip has a plurality of cuts formed therein, said cuts extending from an inner side of the bullet jacket to an outer side of the bullet jacket and having a depth ranging from approximately 0.015 of an inch to approximately 0.450 of an inch.  
   
   
       13 . A method of manufacturing a bullet jacket comprising the steps of placing one or more lengths of forming material in a forming die; and forming the bullet jacket from the forming material, wherein the bullet jacket is formed to comprise a solid base portion and an axially opposite end portion having an outer lip at an upper edge thereof, the end portion defining a cavity having an opening directed towards the end portion and a length which comprises 45 to 70 percent of the total length of the bullet jacket.  
   
   
       14 . The method according to  claim 13 , wherein the cavity is formed to have a length comprising 58 to 61 percent of the total length of the bullet jacket, and the solid base portion is formed to have a weight ranging from approximately 48 percent to 52 percent of a total weight of the bullet jacket.  
   
   
       15 . The method according to  claim 13 , wherein the forming is performed at an internal pressure of approximately 222680 PSI or greater.  
   
   
       16 . The method according to  claim 13 , wherein the forming material used is in the form of tubing or solid rods.  
   
   
       17 . The method according to  claim 13 , wherein the forming die has boat-tail dimensions formed within its cavity and imparts a boat-tail base design upon the bullet jacket as it is being formed.  
   
   
       18 . The method according to  claim 13 , wherein an external punch is used in forming the bullet jacket, said external punch having a plurality of sharp hardened edges which cut the outer lip of the bullet jacket from an inner side of the bullet jacket to an outer side of the bullet jacket at a depth ranging from approximately 0.015 of an inch to approximately 0.450 of an inch.  
   
   
       19 . A bullet comprising a bullet jacket as defined in  claim 1 , and filled with a weighted core material.  
   
   
       20 . The bullet according to  claim 19 , wherein said bullet is capable of expanding on impact when fired at low velocity, and maintains a high weight retention when fired at a high velocity.  
   
   
       21 . The bullet according to  claim 19 , wherein the weighted core material is metal particle and rubber matrix, and the bullet jacket of the bullet expands to approximately double its diameter upon impact at an impact velocity of about 1675 FPS or greater, and the bullet retains about 83% or more of its total mass upon impact at an impact velocity of up to approximately 3300 FPS.