Non-lead composition and method of manufacturing non-lead projectiles and projectile cores therewith

Abstract

A composition and method of manufacturing a non-lead, high density matrix that may be used as a replacement for lead in those instances where lead is used, but its toxicity is undesirable. The composition comprises metal particles combined with synthetic or natural rubber, and is particularly useful in manufacturing non-lead projectiles such as shot and bullets, as well as bullet cores for jacketed bullets.

1 . A non-lead composition comprising metal particles and rubber, wherein the rubber is a moldable, curable rubber having a sufficiently low viscosity to ensure homogeneous mixing of said particles throughout substantially the whole of said composition.  
   
   
       2 . The composition according to  claim 1 , wherein the metal particles include any one or more of the metals selected from the group consisting of copper, tungsten, iron, tin, and other non-lead metals having a high specific gravity, and the rubber is selected from the group consisting of natural rubber, neoprene, polyisoprene and styrene-butadiene rubber.  
   
   
       3 . The composition according to  claim 1 , wherein the metal particles are in the form of powder, granules, flakes, other compactable particulate forms, or a combination thereof.  
   
   
       4 . The composition according to  claim 1 , wherein the rubber has a viscosity ranging from about 48 KU to about 125 KU.  
   
   
       5 . The composition according to  claim 1 , wherein the rubber has a viscosity ranging from about 75 to 80 KU.  
   
   
       6 . The composition according to  claim 1 , wherein the metal particles and rubber are mixed in a ratio ranging from about 25:1 to about 70:1 in parts by weight metal particles to parts by weight rubber.  
   
   
       7 . Use of the composition according to  claim 1  for manufacturing projectiles, projectile cores, wheel weights or fishing weights, or as a lead replacement material in X-ray protecting vests.  
   
   
       8 . A method of manufacturing non-lead projectiles and cores utilized in projectile manufacturing comprising the steps of: 
 mixing metal particles and moldable, curable rubber to form a matrix,    molding the matrix under pressure in a molding apparatus to form a molded projectile or projectile core, and    curing the rubber to form a finished non-lead projectile or projectile core.    
   
   
       9 . The method according to  claim 8 , wherein the molding apparatus is a rotary or single stage tablet pressing machine.  
   
   
       10 . The method according to  claim 8 , wherein the moldable, curable rubber is liquid rubber, and the matrix is dried prior to molding to remove volatile liquids present in the liquid rubber.  
   
   
       11 . The method according to  claim 10 , wherein the dried matrix is granulated by means of a roller compactor and milling machine and passed through a 20 mesh sieve prior to molding.  
   
   
       12 . The method according to  claim 8 , wherein the curing is conducted at a temperature ranging from about 235 F to about 485 F for a duration ranging from about 1 minute to about 20 minutes, and is performed following removal of the molded projectile or projectile core from the molding apparatus, or within the molding apparatus prior to removal.  
   
   
       13 . The method according to  claim 8 , wherein the finished projectile or projectile core is plated using electroplating or other plating methods with a metal selected from the group consisting of zinc, copper, copper alloy, iron, steel, antimony, nickel and tungsten.  
   
   
       14 . The method according to  claim 8 , wherein the metal particles and rubber are mixed in a ratio of about 25:1 to about 70:1 in parts by weight metal particles to parts by weight rubber, and the metal particles range from approximately 5 microns to approximately 30 microns in diameter.  
   
   
       15 . The method according to  claim 8 , wherein the molding pressure ranges from approximately 4,000 PSI to approximately 35,000 PSI, the molding apparatus is a shot molding apparatus, and the projectile formed is non-lead shot having a density ranging from approximately 7 g/cm 3  to 15 g/cm 3 .  
   
   
       16 . The method according to  claim 8 , wherein the molding pressure ranges from approximately 4,000 PSI to approximately 35,000 PSI, the molding apparatus is a bullet-core molding apparatus, and the projectile formed is a bullet-core having a density ranging from approximately 2 g/cm 3  to 15 g/cm 3 .  
   
   
       17 . The method according to  claim 16 , further comprising the steps of seating the bullet core inside a bullet jacket and point-forming to produce a bullet, wherein the seating step is performed separately following the molding step, or simultaneously with the molding step by molding the matrix within the bullet jacket.  
   
   
       18 . The method according to  claim 8 , wherein the molding pressure ranges from approximately 4,000 PSI to approximately 35,000 PSI, the molding apparatus is a bullet molding apparatus, and the projectile formed is a solid, jacketless, non-lead bullet having a density ranging from approximately 2 g/cm 3  to 15 g/cm 3 .  
   
   
       19 . The method according to  claim 8 , wherein the finished non-lead projectile or projectile core is coated with one or more of the coatings selected from polyester TGIC powder coating, polyurethane powder coating and epoxy powder coating.  
   
   
       20 . Non-lead shot, bullet cores or solid, jacketed bullets manufactured according to the method as defined in  claim 8.