How to coat a firearm barrel

Abstract

The present invention relates to a method for providing a coating to the inner surface of a barrel of a small- or medium-caliber firearm, wherein the inner surface defines the internal volume, and the method provides a firearm including the barrel to be processed in a reaction chamber, and provides a cylindrical electrode having an outer surface and including a target material substantially coaxially within the barrel, closes the reaction chamber, reduces the pressure to a predetermined pressure value, supplies gas to the reaction chamber, thereby supplying gas into the internal volume, and raises the pressure within the reaction chamber to an operating pressure, using the electrode as a target cathode and the barrel as an anode. The process includes the steps of: applying a first electric field to the electrode to activate the gas into a plasma gas; using the plasma gas to remove the target material and deposit it on the inner surface; turning off the first electric field; stopping the gas supply; returning the reaction chamber to atmospheric pressure; and removing the firearm, including the processed barrel, from the reaction chamber, wherein the distance between the outer surface of the electrode and the inner surface of the barrel is at least 0.5 mm, the electric field is applied for a time long enough to form a layer of the target material on the inner surface of the barrel, and the product of the operating pressure and the distance between the electrode and the inner surface is 10 -5 This concerns the method of Torr.cm ~ 45 Torr.cm.

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