Subsonic polymeric ammunition

Abstract

The present invention provides a subsonic ammunition including a polymeric casing body comprising a generally cylindrical hollow polymer body having a body base at a first end thereof and a mouth at a second end to define a propellant chamber; a propellant insert positioned in the propellant chamber to reduce the internal volume of the propellant chamber, wherein the propellant chamber has an internal volume that is between 25 and 80% less than the open internal volume of a standard casing of equivalent caliber; a propellant disposed and confined within the propellant chamber; a primer insert positioned at the body base and in communication with the propellant chamber; a primer disposed in the primer insert in combustible communication with the propellant; and a projectile frictionally fitted in the mouth in combustible communication with the propellant.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]Not applicable.TECHNICAL FIELD OF THE INVENTION[0002]The present invention generally relates to ammunition articles, and more particularly to subsonic ammunition casings and ammunition casing propellant inserts formed from polymeric materials.STATEMENT OF FEDERALLY FUNDED RESEARCH[0003]Not applicable.INCORPORATION-BY-REFERENCE OF MATERIALS FILED ON COMPACT DISC[0004]Not applicable.BACKGROUND OF THE INVENTION[0005]Without limiting the scope of the invention, its background is described in connection with lightweight polymer subsonic ammunition casing and more specifically to a lightweight polymer subsonic ammunition casing having a propellant insert positioned in the propellant chamber to reduce the internal volume of the propellant chamber.[0006]Generally, there are two types of ammunition: supersonic ammunition, which fires projectiles with velocities exceeding the speed of sound; and subsonic ammunition, which fires projectiles with vel...

AI Technical Summary

Benefits of technology

[0009]The present invention provides a subsonic ammunition including a polymeric casing body comprising a generally cylindrical hollow polymer body having a body base at a first end thereof, and a mouth at a second end, to define a propellant chamber; a propellant insert positioned in the propellant chamber to reduce the internal volume of the propellant chamber, wherein the propellant chamber has an internal volume that is between 25 and 80% less than the open internal volume of a standard casing of equivalent caliber; a propellant disposed and confined within the propellant chamber; a primer insert positioned at the body base and in communication with the propellant chamber; a primer disposed in the primer insert in combustible communication with the propellant; and a projectile frictionally fitted in the mouth in combustible communication with the propellant. The projectile does not exceed the velocity of 1200 feet per second at sea level under standard atmospheric conditions when fired. The projectile may be secured to the mouth by a mechanical interference, adhesive, ultrasonic welding, the combination of molding in place and adhesive, and hot crimping after the act of molding. The polymer body may include a material selected from the group consisting of polyphenylsulfone, polycarbonate, and polyamide. The subsonic ammunition may further include at least one additive selected from the group consisting of plasticizers, lubricants, molding agents, fillers, thermo-oxidative stabilizers, flame-retardants, coloring agents, compatibilizers, impact modifiers, release agents, reinforcing fibers and reinforcing agents. The propellant insert may have a substantially cylindrical shape, a free formed shape, a one or more ribs extending into the propellant chamber or a radial cross-section selected from the group consisting of circular, ovoid, octagonal, hexagonal, triangular, star, ribbed, square or an irregular shape along its longitudinal length. The radial size of the propellant chamber may taper along its longitudinal direction. The polymeric casing body and propellant insert may be formed of the same or different polymeric materials.

[0010]The propellant chamber may be formed of a separate propellant insert disposed within the internal cavity of the generally cylindrical hollow polymer body. The internal volume may be about 25.1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, or 80% less than the open internal volume of a standard casing of equivalent caliber.

[0011]The present invention provides a subsonic ammunition case having a polymeric casing body comprising a generally cylindrical hollow polymer body having an body base at a first end thereof and a mouth at a second end to define a propellant chamber; a propellant insert positioned in the propellant chamber to reduce the internal volume of the propellant chamber, wherein the propellant chamber has an internal volume that is between 25 and 80% less than the open internal volume of a standard casing of equivalent caliber; a primer insert positioned at the body base and in communication with the propellant chamber; and a primer disposed in the primer insert in combustible communication with the propellant.

Problems solved by technology

Unfortunately, this empty volume can cause numerous problems including inhibition of proper propellant burn, inconsistent propellant positioning, reduced accuracy and propellant detonation caused by extremely high propellant burn rates.

Finally, usage of subsonic ammunition, and its attending lower combustion pressures, frequently results in the inability to efficiently cycle semi-automatic or fully automatic weapons where the propellant charge must produce sufficient gas pressure and / or volume to accelerate the projectile and to cycle the firing mechanism.

With a reduced quantity of propellant, subsonic ammunition generally fails to produce sufficient pressure to properly cycle the firing mechanism.

However, the results of such prior attempts to solve the production of reliable subsonic cartridges have failed and let to subsonic rounds that have a larger variation in velocity and variance in accuracy potential.

In addition the use of polymer ammunition results in additional drawbacks, e.g., the possibility of the projectile being pushed into the cartridge casing, the bullet pull being too light such that the bullet can fall out, the bullet pull being too insufficient to create sufficient chamber pressure, the bullet pull not being uniform from round to round, and portions of the cartridge casing breaking off upon firing, causing the weapon to jam or damage, or danger when subsequent rounds are fired or when the casing portions themselves become projectiles.

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