Reduced drag projectiles
First Claim
Patent Images
1. A low caliber ammunition cartridge, comprising:
- a case comprising a base portion and a case wall extending forward from the base portion to a forward edge of the case wall defining a case cavity and a forward case mouthpropellant disposed inside the case cavity for producing a quantity of propellant gas;
a primer housing disposed in a hole defined by the base portion of the case, and a priming material disposed inside the primer housing for igniting the propellant;
a projectile secured in the mouth of the casing, the projectile comprising a unitary projectile body having a rearward tail portion, a forward nose portion, and a barrel engaging portion extending between and unitary with the nose portion and the tail portion, the barrel engaging portion including a monolithic portion, the monolithic portion having three circumferential grooves spaced intermediate the tail portion and the nose portion, each of the circumferential grooves has an undercut;
the projectile further comprising three overmolded polymer bands disposed in the three circumferential grooves, each of the three overmolded bands conforming to the shape of the respective groove.
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Accused Products
Abstract
A cartridge comprising an elongate rifle bullet with a plurality of circumferential grooves having overmolded polymer therein defining embedded polymer rings. The cartridge further having a case and propellant. 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. The bands offering reduction of the metal to metal contact between the bullet and the barrel while not diminishing the ballistic coefficient of the bullet.
42 Citations
16 Claims
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1. A low caliber ammunition cartridge, comprising:
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a case comprising a base portion and a case wall extending forward from the base portion to a forward edge of the case wall defining a case cavity and a forward case mouth propellant disposed inside the case cavity for producing a quantity of propellant gas; a primer housing disposed in a hole defined by the base portion of the case, and a priming material disposed inside the primer housing for igniting the propellant; a projectile secured in the mouth of the casing, the projectile comprising a unitary projectile body having a rearward tail portion, a forward nose portion, and a barrel engaging portion extending between and unitary with the nose portion and the tail portion, the barrel engaging portion including a monolithic portion, the monolithic portion having three circumferential grooves spaced intermediate the tail portion and the nose portion, each of the circumferential grooves has an undercut; the projectile further comprising three overmolded polymer bands disposed in the three circumferential grooves, each of the three overmolded bands conforming to the shape of the respective groove. - View Dependent Claims (2)
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3. A low caliber ammunition cartridge, comprising:
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a case comprising a base portion and a case wall extending forward from the base portion to a forward edge of the case wall defining a case cavity and a forward case mouth propellant disposed inside the case cavity for producing a quantity of propellant gas; a primer housing disposed in a hole defined by the base portion of the case, and a priming material disposed inside the primer housing for igniting the propellant; a projectile secured in the mouth of the casing, the projectile comprising a unitary projectile body having a rearward tail portion, a forward nose portion, and a barrel engaging portion extending between and unitary with the nose portion and the tail portion, the barrel engaging portion having a monolithic portion and a plurality of circumferential grooves positioned on the monolithic portion; the projectile further comprising a plurality of overmolded polymer bands disposed respectively in each of the plurality of circumferential grooves, each band conforming to the shape of the respective groove and secured therein; an upper portion of the case wall is swaged or crimped inwardly to form a seal between the case wall and the projectile for closing the opening and preventing communication between the propellant in the cavity and an atmosphere outside of the ammunition cartridge; and the forward edge of the case wall is at one of the plurality of overmolded bands. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11)
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12. A low caliber ammunition cartridge, comprising:
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a case comprising a base portion and a case wall extending forward from the base portion to a forward edge of the case wall defining a case cavity and a forward case mouth propellant disposed inside the case cavity for producing a quantity of propellant gas; a primer housing disposed in a hole defined by the base portion of the case, and a priming material disposed inside the primer housing for igniting the propellant; a projectile secured in the mouth of the casing, the projectile comprising a unitary projectile body having an exterior surface, a rearward tail portion, a forward nose portion with a nose tip, and a barrel engaging portion extending between and unitary with the nose portion and the tail portion, the body having an interior surface defining a central cavity extending rearwardly from the nose tip, whereby a projectile wall is defined between the interior surface and the exterior surface, the projectile body having a circumferential groove cut inwardly into the exterior surface of the projectile body, the interior surface not having any structure thereon reflective of the circumferential groove; an overmolded polymer band in the groove, the band having an outer surface that is flush with and continuous with respect to the exterior surface of the projectile body. - View Dependent Claims (13, 14, 15, 16)
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Specification