US Government As Represented by the Secretary of the Army

Paul J Conroy

Charles Stanley Leveritt

James Hirvonen

John D Demaree

James M Garner

Eric J Robinette

John R Schmidt

Raymond A Wildman

Andrew T Gaynor

Daniel R Gubernat

A method of manufacturing and optimizing energetic propellant grains includes generating an optimal surface area to mass fraction burned ratio profile for a predetermined solid structure including propellant grains; using the profile as a target function of a topological optimization process to generate a 3D form of a propellant grain; developing a negative of the 3D form of the propellant grain; mixing and densifying the negative with an energetic material in an uncured form in a mixer to create a structure including the energetic material and embedded negative; and solvating the negative from the structure, wherein the negative comprises a 3D propellant grain. The developing of the negative of the 3D form of the propellant grain may occur using a predetermined material in an additive manufacturing process. The negative may be soluble in the predetermined material, and the energetic material may be insoluble in the predetermined material.

Propellant grain for optimizing the interior ballistic performance of a weapon

A jacketed bullet having a penetrator constructed of a hard material in line with a slug having a lower modulus. At least a portion of both the slug and the penetrator are then encased by a metal jacket. A plurality of circumferentially spaced and axially extending flutes are formed along the slug and possibly the penetrator. These flutes receive deformation of the jacket upon firing of the bullet into a rifled gun bore to thereby reduce friction between the bullet and the gun bore during operation.

Jacketed bullet

A dynamic process for increasing the wear life of ferrous articles subjected to a high-temperature environment created by combustion of a propellant or fuel comprises selecting the propellant or fuel so that its combustion products include relatively large amounts of nitrogen, which nitrogen forms a protective nitride layer on the surface of the ferrous article. Disclosed is a specific embodiment of the invention for prolonging the wear life of gun barrels.

Dynamic process for enhancing the wear resistance of ferrous articles

A body of iron, steel or other such ferrous material is protected from thermochemical erosion by a layer of an iron nitride having a relatively low nitrogen content. The atomic percentage of nitrogen in the iron nitride layer is no greater than 20%, and in specific embodiments is in the range of 10-15%. The nitride layer may have a layer of a refractory material deposited thereatop. Some refractory materials include metals such as chromium. The invention has specific utility for protecting gun barrels, turbines, internal combustion engines, drilling equipment, machine tools, aerospace systems and chemical reactors which are exposed to extreme conditions of temperature and pressure. Specifically disclosed is a gun barrel which incorporates the invention.

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Churchville, MD, United States of America

Paul J Conroy