Projectiles with insert-molded polymer tips
Aspects of the disclosure are directed to manufacturing an insert-molded expanding projectile. Aspects of the disclosure include locating a portion of a projectile body within a converging tip mold, the projectile body including a metal jacket extending from a tail portion to a nose portion and surrounding an interior solid core. The metal jacket and nose portion may be tapered in a forward direction to an annular forward edge defining an opening to an undercut interior cavity. Melted polymer may be injected into the converging tip mold and allowed to cool thereby forming a polymer tip having a main portion forward of the opening and a tip retention portion filling the undercut interior cavity and having a shape corresponding to the undercut interior cavity to retain the polymer tip in place.
1. A method of manufacturing an insert-molded expanding projectile comprising:
obtaining a projectile body including a metal jacket extending from a tail portion to a nose portion and surrounding an interior solid core, the metal jacket tapered at the nose portion in a forward direction to an annular forward edge, the annular forward edge defining an opening in the metal jacket to a forward facing interior surface of the interior solid core, the projectile body including an interior cavity extending from the opening in a rearward direction to a cavity end point within the projectile body, the interior cavity defined by the forward facing interior surface and an interior surface of the metal jacket forward of the forward facing interior surface;
introducing a liquid elastomer into the interior cavity, thereby filling the interior cavity from the cavity end point to a fill point spaced forward of the cavity end point, the liquid elastomer forming a forward facing elastomer surface at the fill point, the forward facing elastomer surface and the interior surface of the metal jacket, forward of the forward facing elastomer surface, defining an undercut interior cavity portion;
obtaining a converging tip mold configured to form a polymer tip, the converging tip mold having an injection port extending to a mold cavity;
locating at least a forward portion of the projectile body within the converging tip mold, whereby the mold cavity is defined by at least the undercut interior cavity portion and a converging interior mold surface spaced forward of the annular forward edge, the interior mold surface in flush alignment with an exterior surface of the metal jacket;
injecting a melted polymer into the converging tip mold, thereby filling the undercut interior cavity portion and the converging tip mold with the melted polymer; and
allowing the melted polymer to cool to form the polymer tip, the polymer tip having an exterior substantially flush with the exterior surface of the metal jacket, the polymer tip having a main portion forward of the opening and a widening tip retention portion filling the undercut interior cavity portion, the widening tip retention portion having a shape corresponding to the undercut interior cavity portion to retain the polymer tip in place.
2. The method of claim 1 , wherein:
allowing the melted polymer to cool thereby bonds, via adhesion, the widening tip retention portion to the forward facing interior surface and to the interior surface of the metal jacket forward of the forward facing interior surface to retain the polymer tip in place.
3. The method of claim 1 , wherein:
the forward facing elastomer surface is an asymmetric interior surface; and
injecting the melted polymer into the converging tip mold thereby fills the undercut interior cavity portion extending from the opening to the asymmetric interior surface.
4. The method of claim 1 , wherein:
introducing the liquid elastomer occurs before locating at least the forward portion of the projectile body within the converging tip mold.
5. The method of claim 1 , further comprising:
allowing the liquid elastomer to cool;
wherein allowing the liquid elastomer to cool thereby forms the forward facing elastomer surface.
6. The method of claim 1 , wherein:
the forward portion of the metal jacket includes a plurality of longitudinal skives spaced circumferentially about the metal jacket and extending in a rearward direction, from the annular forward edge, to a skive end point at the nose portion.
7. The method of claim 1 , wherein:
an axial distance from the forward facing elastomer surface to the opening is in the range of 5 millimeters to 10 millimeters.
8. The method of claim 1 , wherein:
an axial distance from the forward facing elastomer surface to the opening is in the range of 5% to 20% the length of the projectile body.
9. The method of claim 1 , wherein:
the metal jacket and the interior solid core of the projectile body is a unitary metal structure.
10. The method of claim 1 , wherein the interior solid core comprises lead and the metal jacket comprises copper.
11. An insert-molded expanding projectile comprising:
a projectile body including a metal jacket extending from a tail portion to a nose portion and surrounding an interior solid core, the metal jacket tapered at the nose portion in a forward direction to an annular forward edge, the annular forward edge defining an opening in the metal jacket to a forward facing interior surface of the interior solid core, the projectile body including an interior cavity extending from the opening to a cavity end point within the body, the interior cavity defined by the forward facing interior surface and an interior surface of the metal jacket forward of the forward facing interior surface; and
an insert-molded elastomer portion filling the interior cavity from the cavity end point to a fill point forward of the cavity end point, the insert-molded elastomer portion having a forward facing elastomer surface, the forward facing elastomer surface and the interior surface of the metal jacket, forward of the forward facing elastomer surface, defining an undercut interior cavity portion extending from the opening to the forward facing elastomer surface
an insert-molded polymer tip having an exterior surface substantially flush with an exterior surface of the metal jacket, the insert-molded polymer tip having a main portion forward of the opening and a widening tip retention portion filling the undercut interior cavity portion, the widening tip retention portion having a shape corresponding to the undercut interior cavity portion to retain the insert-molded polymer tip in place.
12. The insert-molded projectile of claim 11 , wherein:
the metal jacket includes an annular groove cut into the interior surface of the metal jacket forward of the forward facing elastomer surface; and
the interior cavity is further defined by the annular groove.
13. The insert-molded projectile of claim 11 , wherein:
the metal jacket includes an annular shoulder along the interior surface of the metal jacket forward of the forward facing elastomer surface;
the interior cavity is further defined by the annular shoulder.
14. The insert-molded projectile of claim 11 , wherein:
the annular forward edge includes a plurality of longitudinal skives spaced circumferentially about the metal jacket and extending in a rearward direction, relative to the annular forward edge, to a skive end point at the nose portion.
15. The insert-molded projectile of claim 11 , wherein:
the forward facing elastomer surface is an asymmetric interior surface.
16. The insert-molded projectile of claim 11 , wherein:
an axial distance from the forward facing elastomer surface to the opening is in the range of 5 millimeters to 10 millimeters.
17. The insert-molded projectile of claim 11 , wherein:
an axial distance from the forward facing elastomer surface to the opening is in the range of 5% to 20% the length of the projectile body.
18. The insert-molded projectile of claim 11 , wherein:
the metal jacket and the interior solid core is a unitary metal structure.
19. The insert-molded projectile of claim 11 , wherein the interior solid core comprises lead and the metal jacket comprises copper.
20. A method of forming a projectile, comprising:
arranging for a coil of metal wire to be shipped from a first geographic location to a second geographic location, wherein metal wire has a standard wire gauge, and wherein the first geographic location and the second geographic location are separated by a distance of more than 500 miles;
feeding a length of the metal wire through a plurality of rollers to straighten the metal wire;
cutting the metal wire to form a billet, the billet having a billet diameter and a billet length;
placing the billet in a lumen defined by a first die, the lumen having a lumen diameter that is greater than the billet diameter and a lumen length that is greater than the billet length;
positioning a pin in the lumen defined by a first die on a first side of the billet and positioning a tool in the lumen defined by the first die on a second side of the billet so that the billet is disposed between the pin and the tool;
moving one of the tool and the pin toward the other of the tool and the pin so that the billet is squeezed between the tool and the pin thereby forming a workpiece defining a workpiece cavity, the workpiece having a workpiece diameter that is greater than the billet diameter and a workpiece length that is smaller than the billet length;
placing the workpiece in a die cavity defined by a second die, the die cavity having a tapered portion, the tapered surface having a taper radius that decreases as the tapered surface extends in a distal direction;
inserting an end of a drive pin into a proximal end of the die cavity;
pushing the workpiece against the tapered surface so that a distal portion of the workpiece is deformed to form a projectile body defining an interior cavity, the projectile body having a nose portion and a tail portion, the nose portion tapered in a forward direction to an annular forward edge, the annular forward edge defining an opening to the interior cavity, the interior cavity extending in a rearward direction from the opening to a cavity end point within the projectile body;
introducing a liquid elastomer into the interior cavity, thereby filling the interior cavity from the cavity end point to a fill point spaced forward of the cavity end point, the liquid elastomer forming a forward facing elastomer surface at the fill point, the forward facing elastomer surface and the interior surface of the metal jacket, forward of the forward facing elastomer surface, defining an undercut interior cavity portion;
obtaining a converging tip mold configured to form a polymer tip, the converging tip mold having an injection port extending to a mold cavity;
locating at least a forward portion of the projectile body within the converging tip mold, whereby the mold cavity is defined by at least the undercut interior cavity portion and a converging interior mold surface spaced forward of the annular forward edge, the interior mold surface in flush alignment with an exterior surface of the metal jacket;
injecting a melted polymer into the converging tip mold, thereby filling the undercut interior cavity portion and the converging tip mold with the melted polymer; and
allowing the melted polymer to cool to form the polymer tip, the polymer tip having an exterior substantially flush with the exterior surface of the metal jacket, the polymer tip having a main portion forward of the opening and a widening tip retention portion filling the undercut interior cavity portion, the widening tip retention portion having a shape corresponding to the undercut interior cavity portion to retain the polymer tip in place.