Jacketed bullet and methods of making the same

Abstract

Jacketed firearms projectile having a jacket thickness less than approximately 0.025 inches thick are described, where the density of the projectile core has been selected so that the jacketed projectile has a weight that is at least substantially the same as a reference firearms projectile, such as a lead projectile, having substantially the same size and shape. In one aspect, the projectile is a frangible projectile. In another aspect, the projectile is lead-free. In yet another aspect, the projectile is incorporated in a cartridge. Methods for forming the projectile and forming cartridges containing the projectiles are also disclosed.

What is claimed is:  
     
         1 . A frangible bullet having a size, shape, and weight, the bullet comprising: 
 a frangible bullet core having a bullet core density; and    a frangible bullet jacket comprising a jacketing material that at least substantially encloses the bullet core, wherein the jacket has a jacket thickness in the range of approximately 0.005 inches and approximately 0.025 inches; and    wherein the bullet core has a core density that is selected so that the size, shape, and weight of the frangible bullet is at least substantially the same as a corresponding size, shape, and weight of a reference bullet having a core that is at least substantially formed from lead.    
     
     
         2 . The frangible bullet of  claim 1 , where the reference bullet is at least substantially enclosed by a reference bullet jacket comprising a reference jacket material having a jacket thickness of at least approximately 0.012 inches.  
     
     
         3 . The frangible bullet of  claim 2 , wherein the jacketing material is the same as the reference jacket material.  
     
     
         4 . The frangible bullet of  claim 1 , wherein the frangible bullet core comprises tungsten or tungsten alloy.  
     
     
         5 . The frangible bullet of  claim 4 , wherein the frangible bullet core comprises an alloy of tungsten, nickel, and iron.  
     
     
         6 . The frangible bullet of  claim 1 , wherein the frangible bullet core has been sintered.  
     
     
         7 . The frangible bullet of  claim 1 , wherein the bullet frangible core has not been sintered.  
     
     
         8 . The frangible bullet of  claim 1 , wherein the frangible bullet core comprises a metallic powder and a binder.  
     
     
         9 . The frangible bullet of  claim 8 , wherein the binder includes a metal binder.  
     
     
         10 . The frangible bullet of  claim 9 , wherein the binder includes tin.  
     
     
         11 . The frangible bullet of  claim 8 , wherein the binder includes a non-metal binder.  
     
     
         12 . The frangible bullet of  claim 11 , wherein the non-metal binder includes an epoxy.  
     
     
         13 . The frangible bullet of  claim 1 , wherein the frangible bullet core is substantially lead-free.  
     
     
         14 . The frangible bullet of  claim 1 , wherein the frangible bullet core is lead-free.  
     
     
         15 . The frangible bullet of  claim 1 , wherein the bullet core density is selected to be less than the density of lead.  
     
     
         16 . The frangible bullet of  claim 1 , wherein the bullet core density is selected to be greater than the density of lead.  
     
     
         17 . The frangible bullet of  claim 1 , wherein the bullet core comprises ferrotungsten alloy, the jacketing material is copper metal, and the jacket thickness is approximately 0.007 inches.  
     
     
         18 . The frangible bullet of  claim 1 , in combination with a case, a propellant charge within the case, and a primer charge within the case to form a cartridge.  
     
     
         19 . The frangible bullet of  claim 18 , wherein a major diameter of the frangible bullet is approximately 0.22 inches, the jacket thickness is in the range of approximately 0.006-0.008 inches, and the density of the bullet core is in the range of approximately 10.6-10.7 grams/cm 3 .  
     
     
         20 . The frangible bullet of  claim 18 , wherein a major diameter of the frangible bullet is approximately 0.36 inches, the jacket thickness is in the range of approximately 0.006-0.008 inches, and the density of the bullet core is in the range of approximately 11.04-11.09 grams/cm 3 .  
     
     
         21 . The frangible bullet of  claim 18 , wherein a major diameter of the frangible bullet is approximately 0.45 inches, the jacket thickness is in the range of approximately 0.006-0.008 inches, and the density of the bullet core is in the range of approximately 11.02-11.06 grams/cm 3 .  
     
     
         22 . The frangible bullet of  claim 18 , wherein a major diameter of the frangible bullet is approximately 0.22 inches, the jacket thickness is approximately 0.007 inches, and the density of the bullet core is approximately 10.68 grams/cm 3 .  
     
     
         23 . The frangible bullet of  claim 18 , wherein a major diameter of the frangible bullet is approximately 0.36 inches, the jacket thickness is approximately 0.007 inches, and the density of the bullet core is approximately 11.07 grams/cm 3 .  
     
     
         24 . The frangible bullet of  claim 18 , wherein a major diameter of the frangible bullet is approximately 0.45 inches, the jacket thickness is approximately 0.007 inches, and the density of the bullet core is approximately 11.04 grams/cm 3 .  
     
     
         25 . A lead-free bullet having a size, shape, and weight, the bullet comprising: 
 a lead-free bullet core having a bullet core density;    a bullet jacket comprising a jacketing material that at least substantially encloses the bullet core, wherein the jacket has a jacket thickness in the range of approximately 0.005 inches and approximately 0.025 inches; and    wherein the bullet core has a core density that is selected so that the size, shape, and weight of the lead-free bullet is at least substantially the same as a corresponding size, shape, and weight of a reference bullet having a core that is at least substantially formed from lead.    
     
     
         26 . The lead-free bullet of  claim 25 , where the reference bullet is at least substantially enclosed by a reference bullet jacket comprising a reference jacket material having a jacket thickness of at least approximately 0.012 inches.  
     
     
         27 . The lead-free bullet of  claim 26 , wherein the jacketing material is the same as the reference jacket material.  
     
     
         28 . The lead-free bullet of  claim 25 , wherein the lead-free bullet core comprises tungsten or tungsten alloy.  
     
     
         29 . The lead-free bullet of  claim 28 , wherein the lead-free bullet core comprises an alloy of tungsten, nickel, and iron.  
     
     
         30 . The lead-free bullet of  claim 25 , wherein the lead-free bullet core comprises a metallic powder and a binder.  
     
     
         31 . The lead-free bullet of  claim 30 , wherein the lead-free bullet core has been sintered.  
     
     
         32 . The lead-free bullet of  claim 30 , wherein the binder includes a metal binder.  
     
     
         33 . The lead-free bullet of  claim 32 , wherein the binder includes tin.  
     
     
         34 . The lead-free bullet of  claim 30 , wherein the binder includes an epoxy.  
     
     
         35 . The lead-free bullet of  claim 25 , wherein the lead-free bullet core is frangible.  
     
     
         36 . The lead-free bullet of  claim 25 , wherein the bullet core density is selected to be less than the density of lead.  
     
     
         37 . The lead-free bullet of  claim 25  wherein the bullet core density is selected to be greater than the density of lead.  
     
     
         38 . The lead-free bullet of  claim 25 , wherein the lead-free bullet core comprises ferrotungsten alloy, the jacketing material includes copper, and the jacket thickness is approximately 0.007 inches.  
     
     
         39 . The lead-free bullet of  claim 25 , in combination with a case, a propellant charge within the case, and a primer charge within the case to form a cartridge.  
     
     
         40 . A method of forming a jacketed bullet, comprising the steps of: 
 selecting a reference bullet having a desired bullet size, bullet shape, and bullet weight, where the reference bullet includes a bullet core having a reference bullet core composition;    selecting a jacket material having a jacket density for the jacketed bullet;    selecting a jacket thickness for the jacketed bullet;    calculating a core density, a core size, and a core shape for a target bullet core, so that when the target bullet core is jacketed by the selected jacket material at the selected jacket thickness the resulting jacketed bullet will have the desired bullet size, desired bullet shape, and desired bullet weight;    preparing the target bullet core having the calculated core density, size, and shape, where the target bullet core composition is distinct from the reference bullet core composition; and    jacketing the target bullet core with the selected jacket material at the selected jacket thickness to produce the jacketed bullet.    
     
     
         41 . The method of  claim 40 , wherein the reference bullet core composition includes lead.  
     
     
         42 . The method of  claim 41 , wherein the reference bullet is a jacketed bullet.  
     
     
         43 . The method of  claim 40 , wherein the target bullet core is at least substantially lead-free.  
     
     
         44 . The method of  claim 43 , wherein the step of preparing the target bullet core comprises cold-pressing the target bullet core.  
     
     
         45 . The method of  claim 43 , wherein the step of preparing the target bullet core comprises sintering the target bullet core.  
     
     
         46 . The method of  claim 40 , wherein the target bullet core composition includes tungsten or tungsten alloy.  
     
     
         47 . The method of  claim 40 , wherein the target bullet composition comprises a metallic powder and a tin binder.  
     
     
         48 . The method of  claim 40 , wherein the target bullet composition comprises a metallic powder and an epoxy binder.  
     
     
         49 . The method of  claim 40 , wherein the selected jacket thickness is less than approximately 0.01 inches.  
     
     
         50 . The method of  claim 49 , wherein the selected jacket thickness is in the range of approximately 0.006 and approximately 0.008 inches.  
     
     
         51 . The method of  claim 40 , wherein the jacketed bullet is a frangible bullet.  
     
     
         52 . The method of  claim 40 , further comprising the step of mounting the jacketed bullet in an open end of a casing containing a propellant charge and a primer charge to form a cartridge.