A barrel having a body including an elongate tubular structure extending from a breach end to a muzzle end; a projectile bore extending from a projectile chamber to the muzzle end; and a one or more tubular recesses formed in the body, wherein each tubular recess is defined by an elongate hole extending from an open end formed in an area proximate the muzzle end.

A barrel having a body including an elongate tubular structure extending from a breach end to a muzzle end; a projectile bore extending from a projectile chamber to the muzzle end; and a one or more tubular recesses formed in the body, wherein each tubular recess is defined by an elongate hole extending from an open end formed in an area proximate the muzzle end.

A method making a gun barrel liner includes depositing material on a mandrel that has ribs or ridges corresponding to the rifling grooves in the liner. The material may be deposited using plasma spraying, with sprayed splats of material re-melted after deposition for at least part of the deposition process to reduce or eliminate porosity in the deposited material. The mandrel may be made of metal, such as a high thermal conductivity metal such as copper. The mandrel may have a channel therein or therethrough. The channel may facilitate flow of liquid though the mandrel, one example of such a liquid being a coolant (such as water), used to remove heat produced during the material deposition. Another liquid passed through the channel may be an etchant (or other fluid) that is used to dissolve or otherwise remove the mandrel after the material of the gun barrel liner has been deposited.

A method making a gun barrel liner includes depositing material on a mandrel that has ribs or ridges corresponding to the rifling grooves in the liner. The material may be deposited using plasma spraying, with sprayed splats of material re-melted after deposition for at least part of the deposition process to reduce or eliminate porosity in the deposited material. The mandrel may be made of metal, such as a high thermal conductivity metal such as copper. The mandrel may have a channel therein or therethrough. The channel may facilitate flow of liquid though the mandrel, one example of such a liquid being a coolant (such as water), used to remove heat produced during the material deposition. Another liquid passed through the channel may be an etchant (or other fluid) that is used to dissolve or otherwise remove the mandrel after the material of the gun barrel liner has been deposited.

A method of forming a gun barrel is disclosed that includes applying one or more coatings to the gun barrel such as just a top coating, or a bond coating and then a top coating. The method may also include (before applying one or more coatings): threading an outer surface of the gun barrel proximate a first end of the gun barrel; threadedly coupling the first end of the gun barrel to a gun chamber; fixedly coupling the gun barrel to the gun chamber. The method may also include heat treating the coating layer(s), contouring the outer coating layer, applying a ceramic top coating to the contoured outer coating layer of the gun barrel, and/or sealing the gun barrel with a liquid metal sealer.

A method of forming a gun barrel is disclosed that includes applying one or more coatings to the gun barrel such as just a top coating, or a bond coating and then a top coating. The method may also include (before applying one or more coatings): threading an outer surface of the gun barrel proximate a first end of the gun barrel; threadedly coupling the first end of the gun barrel to a gun chamber; fixedly coupling the gun barrel to the gun chamber. The method may also include heat treating the coating layer(s), contouring the outer coating layer, applying a ceramic top coating to the contoured outer coating layer of the gun barrel, and/or sealing the gun barrel with a liquid metal sealer.

A friction preventing apparatus and a method of manufacturing the same are provided. The apparatus includes: a first object; a second object spaced apart from the first object and facing the first object; and a plurality of charged nanoparticles provided on a surface of one of the first and second objects, such that the nanoparticles are disposed between the first object and the second object. A potential difference is formed between the first and second objects. The nanoparticles may be positively charged and may adhere to the first object, and the first object has a potential lower than a potential of the second object. The nanoparticles may be negatively charged and may adhere to the second object, and the second object has a potential higher than a potential of the first object.

A friction preventing apparatus and a method of manufacturing the same are provided. The apparatus includes: a first object; a second object spaced apart from the first object and facing the first object; and a plurality of charged nanoparticles provided on a surface of one of the first and second objects, such that the nanoparticles are disposed between the first object and the second object. A potential difference is formed between the first and second objects. The nanoparticles may be positively charged and may adhere to the first object, and the first object has a potential lower than a potential of the second object. The nanoparticles may be negatively charged and may adhere to the second object, and the second object has a potential higher than a potential of the first object.

A device is provided for repairing erosion damage to a bore of a railgun with metal powder. The bore has a surface contour that extends longitudinally of the railgun. The device includes a housing, a profilometer sensor and a nozzle. The housing has a configuration that conforms to the surface contour and an upstream face on a longitudinal end. The profilometer sensor mounts to the upstream face to measure depth of the erosion and indicate a divot in the bore that involves repair to match the surface contour. The nozzle mounts to the upstream face to spray the metal powder from a reservoir within the housing in response to the divot indicated by the profilometer.

A device is provided for repairing erosion damage to a bore of a railgun with metal powder. The bore has a surface contour that extends longitudinally of the railgun. The device includes a housing, a profilometer sensor and a nozzle. The housing has a configuration that conforms to the surface contour and an upstream face on a longitudinal end. The profilometer sensor mounts to the upstream face to measure depth of the erosion and indicate a divot in the bore that involves repair to match the surface contour. The nozzle mounts to the upstream face to spray the metal powder from a reservoir within the housing in response to the divot indicated by the profilometer.