Gun barrel equipped with alternating variable pitch rifling
AssigneeU.S. Government as represented by the Secretary of the Army
InventorsDavid Rophael, Adam L. Foltz
Life of this patent
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Abstract
A rifled weapon barrel has increases the piezometric efficiency of the weapon system with varying rifling profiles throughout the barrel to maximize useful work out of the propellant gases. The weapon barrel includes a first rifling section at the breech end which progressively increases in twist rate to induce a torque spike on the projectile and maximize chamber pressure. Next, the weapon barrel includes a second rifling section which progressively decreases the twist rate to a level that may be unsuitable for aerodynamic stability but provides relief from the torque spike while minimizing pressure loss behind the projectile. Finally, the rifle then maintains this twist rate or decreases to increase stability of the projectile before exit.
Claims17
A gun barrel having rifling with a variable twist rate, the gun barrel comprising:
- an open-ended hollow cylinder extending along a longitudinal axis having a chamber end, a muzzle end and an interior surface;
- said interior surface defining rifling wherein a twist rate of the rifling varies along the longitudinal axis such that the rifling further comprises a elevated pressure region located at the breech end and having a progressively increasing twist rate selected to induce a torque spike on a projectile, a relief region having a progressively decreasing twist rate selected to relieve the projectile of the torque spike toward a final twist rate and a stabilizing region located at the muzzle end and having a twist rate equal to or less than the relief region and selected to stabilize the projectile.
A 40 mm gun barrel having rifling with a variable twist rate, the 40 mm gun barrel comprising:
- an open-ended hollow cylinder extending along a longitudinal axis having a chamber end, a muzzle end and an interior surface;
- said interior surface defining rifling wherein a twist rate of the rifling varies along the longitudinal axis such that the rifling further comprises a elevated pressure region located at the chamber end and having a progressively increasing twist rate from 48 inches per revolution to 24 inches per revolution, a relief region having a progressively decreasing twist rate from 24 inches per revolution to 48 inches per revolution and a stabilizing region located at the muzzle end and having a twist rate equal to or less than 48 inches per revolution.
Dependencies are inferred from the claim text.