Bismuth-based firearm projectiles, firearm cartridges including the same, and related methods

Abstract

Bismuth-based firearm projectiles, optionally firearm cartridges containing the same, and methods for forming bismuth-tin-copper alloys or bismuth-nickel alloys and bismuth-based firearm projectiles are disclosed herein. The bismuth-based firearm projectiles include a projectile body comprising a bismuth-tin-copper alloy or bismuth-nickel alloy that forms at least 90 wt % of the projectile body.

We claim: 
     
         1 . A bismuth-based firearm projectile, comprising:
 a projectile body comprising a bismuth-nickel alloy that forms at least 90 weight percent (wt %) of the projectile body;   wherein the bismuth-nickel alloy comprises an alloy of bismuth and nickel; and   wherein the bismuth-nickel alloy comprises 95-99.5 wt % bismuth and 0.5-5 wt % nickel.   
     
     
         2 . The firearm projectile of  claim 1 , wherein the bismuth-nickel alloy comprises at least one of at least 0.5 wt % nickel, at least 0.75 wt % nickel, at most 0.5 wt % nickel, at most 0.75 wt % nickel, at most 1 wt % nickel, at most 1.5 wt % nickel, at most 2 wt % nickel, at most 3 wt % nickel, and at most 5 wt % nickel. 
     
     
         3 . The firearm projectile of  claim 1 , wherein the bismuth-nickel alloy comprises 99-99.5 wt % bismuth and 0.5-1 wt % nickel. 
     
     
         4 . The firearm projectile of  claim 1 , wherein the bismuth-nickel alloy comprises 99.2-99.5 wt % bismuth and 0.5-0.8 wt % nickel 
     
     
         5 . The firearm projectile of  claim 1 , wherein the bismuth-nickel alloy forms at least one of at least 92 wt %, at least 94 wt %, at least 96 wt %, at least 98 wt %, at least 99 wt %, and at most 100 wt % of the projectile body. 
     
     
         6 . The firearm projectile of  claim 1 , further comprising a coating applied to an exterior of the projectile body. 
     
     
         7 . The firearm projectile of  claim 6 , wherein the coating is a copper jacket. 
     
     
         8 . The firearm projectile of  claim 6 , wherein the coating includes one or more of copper, a copper alloy, nickel, a nickel alloy, iron, an iron alloy, zinc, aluminum, tungsten, and gilding metal. 
     
     
         9 . The firearm projectile of  claim 1 , wherein the projectile body comprises a stiffness that is at most 50% of a stiffness of a bismuth-tin projectile body of an equivalent size and shape, wherein the bismuth-tin projectile body consists of a 95Bi5Sn alloy bismuth-tin alloy. 
     
     
         10 . The firearm projectile of  claim 9 , wherein the stiffness of the projectile body is a threshold fraction of the stiffness of the bismuth-tin projectile body, and wherein the threshold fraction is at least one of at least 40%, at least 50%, at least 60%, at least 70%, at most 70%, at most 80%, and at most 90%. 
     
     
         11 . The firearm projectile of  claim 1 , wherein the projectile body comprises a density of at least one of at least 9.4 grams per cubic centimeter (g/cc), at least 9.5 g/cc, at least 9.55 g/cc, at least 9.6 g/cc, at least 9.65 g/cc, at least 9.7 g/cc, at least 9.71 g/cc, at least 9.72 g/cc, at least 9.73 g/cc, at least 9.74 g/cc, at least 9.75 g/cc, at most 9.72 g/cc, at most 9.73 g/cc, at most 9.74 g/cc, at most 9.75 g/cc, at most 9.76 g/cc, and at most 9.78 g/cc. 
     
     
         12 . The firearm projectile of  claim 1 , wherein the nickel is at least substantially dissolved in the bismuth. 
     
     
         13 . The firearm projectile of  claim 1 , wherein the bismuth-nickel alloy comprises one or more Bi—Ni alloy domains. 
     
     
         14 . The firearm projectile of  claim 1 , wherein the bismuth-nickel alloy is one or more of an annealed alloy, a stress-relieved alloy, and a heat-treated alloy. 
     
     
         15 . The firearm projectile of  claim 1 , wherein the bismuth-based firearm projectile is a frangible firearm projectile, wherein the frangible firearm projectile has a weight and is configured to break entirely into small particulate when fired at a metal surface at close range from a firearm cartridge, and wherein the small particulate has a maximum particle weight of 5% of the weight of the frangible firearm projectile. 
     
     
         16 . A firearm cartridge, comprising:
 a casing that defines an internal volume;   a propellant disposed in the internal volume;   a primer disposed in the internal volume and configured to ignite the propellant;   the bismuth-based firearm projectile of  claim 1  at least partially received in the casing.   
     
     
         17 . A bismuth-based firearm projectile, comprising:
 a projectile body comprising a bismuth alloy that forms at least 90 weight percent (wt %) of the projectile body;   wherein the bismuth alloy comprises an alloy of bismuth, tin, and a third metal; and   wherein the bismuth alloy comprises at least 85 wt % bismuth and at least 0.05 wt % of the third metal.   
     
     
         18 . The firearm projectile of  claim 17 , wherein the bismuth alloy comprises 90-99 wt % bismuth, 0.7-9.5 wt % tin, and 0.05-3 wt % of the third metal. 
     
     
         19 . The firearm projectile of  claim 17 , wherein the third metal comprises copper. 
     
     
         20 . The firearm projectile of  claim 17 , wherein the bismuth alloy further comprises a fourth metal, wherein the fourth metal is one of antimony and zinc, and combinations thereof.