REDUCED DRAG PROJECTILES

摘要

Embodiments of the invention include an elongate rifle bullet with a plurality of circumferential grooves having overmolded polymer therein defining embedded polymer rings. Embodiments of the invention include cartridges with propellant and such bullets. In one or more embodiments, the bullet has a body portion and a converging nose portion. The polymer rings have an outer surface that is flush with, that is, conforming to the outer surface of the body. The polymer may have be selected to have a favorable coefficient of friction with respect to the barrel. A feature and advantage of embodiments is that the metal to metal contact between the bullet and the barrel is reduced while not diminishing the ballistic coefficient of the bullet.

主权项

1. A method of manufacturing a bullet comprising:
obtaining a bullet body defining one or more circumferential grooves, the bullet body comprising a body wall extending between an interior wall surface and an exterior wall surface, the interior wall surface defining an interior cavity, the interior cavity fluidly communicating with an opening defined by a forward facing edge of the bullet body, the interior cavity extending rearwardly from the opening to a cavity end point within the bullet body, a core member disposed inside the cavity, the core member comprising a forward facing surface, the core member extending rearwardly from the forward facing surface to the cavity end point within the body, the forward facing surface of the core member and the interior wall surface defining a forward portion of the interior cavity, the forward portion of the interior cavity having a cavity radius, the cavity radius decreasing as the forward portion of the interior cavity extends forward from the forward facing surface of the core member to the opening; inserting the bullet body into a mold with at least one tip sprue and one or more groove sprues; injecting molten polymer into the one or more grooves through the one or more groove sprues; allowing the polymer to cool forming one or more polymer bands, each polymer band being disposed in one of the one or more circumferential grooves; and removing the bullet body from the mold.