This application claims the benefit of U.S. Design patent application 29/444,690, filed Feb. 1, 2013, and entitled “Carbon Removal and Polishing Tool for Rifle Bolts,” the entire contents of which are incorporated herein by reference.
The present disclosure relates to firearm cleaning devices for semiautomatic and fully automatic firearms, and more particularly to devices for removing debris from firearm bolt tails of a breech bolt of the AR-15, an M-16 or derivatives thereof and polishing the same.
Gas operated firearms are efficient but require frequent maintenance. Build ups of debris such as vaporized metals, carbon, and other impurities on the bolt, particularly the bolt tail, may cause the firearm to foul if the debris is not routinely removed.
In gas impingement systems like those found in the AR-15, gas operated firearms extract spent casings and load a new cartridge in the chamber by harnessing energy from high pressure gases generated during firing. High pressure gas is siphoned off from the barrel after a fired bullet passes a gas port. Gas enters the gas port, travels down a gas tube, typically located above the barrel, and into a gas key. The gas key channels the gas into the bolt carrier. The bolt carrier houses the bolt, forming a piston powered by the high pressure gases. The high pressure gas impinges upon the bolt tail, causing the bolt and bolt carrier to move and cycle through the chambering operation.
In order to efficiently transfer the energy contained in the high pressure gas to other portions of the bolt carrier assembly, the bolt tail comprises a bolt tail top and a bolt tail body. Both portions have circular cross sections. The bolt tail top has a concave curvature, having a larger diameter at a first end which curves down to a smaller diameter at a second end where the bolt tail top connects with the cylindrical bolt tail body. In order to ensure proper functionality and reliability, debris must be removed from both portions of the bolt tail and both portions must be polished.
Several debris removal approaches exist. The usual method to clean the bolt tail is to scrape it with a sharp metal object followed by brushing with various solvents and compounds to finally clean and polish the part.
Various tools have been designed to make this task easier. A product called a “Carbon Removal Tool” manufactured by Magna-matic of Waldo, Wis. discloses an adjustable metal scraper featuring a pin which is inserted into the bolt, allowing the adjustable metal scraper to be held against the bolt tail and rotated, thereby removing debris from the bolt tail. This design is disclosed in U.S. Pat. No. 8,327,571 (the '571 patent).
Another approach is disclosed in U.S. Patent Application Publication No. 2011/0113669 (the '669 Application) wherein the bolt tail is first inserted into a channel and rotated against an adjacent scraper blade.
Known cleaning and polishing tools, including those disclosed in the '571 patent and the '669 Application, require a final action to remove the last remaining residue. For example, devices in accordance with the '669 Application accomplish the final cleaning and polishing action by having a user place a polishing pad around the bolt tail and inserting the assembly into an adjustable polishing arm guide hole. The user may press a polishing arm down on the bolt tail and rotate the bolt in order to complete the cleaning process. Additional compounds can be used to facilitate this action.
Existing bolt tail cleaning and polishing solutions are relatively large, making them difficult to carry in a cleaning kit. In fact, many existing devices are larger than the bolt itself. Additionally, existing bolt tail cleaning devices require two separate processes to clean and polish the bolt tail. The first process is used to scrape away the majority of the debris deposited on the bolt tail. The second process is required to fully clean and polish the bolt tail surface.
Given the foregoing, what is needed are devices which remove debris from the bolt tail of a firearm and polish the bolt tail in a single process. Additionally, durable devices are needed which have a small footprint, preferably smaller than a bolt, in order to facilitate carrying the bolt tail cleaner in a cleaning kit. In sum, what is needed is a is a cost effective, durable, portable device which, via a single process, removes debris and polishes the bolt tail, thereby enabling more rapid and complete cleaning of the bolt tail both in the barracks and in the field.
The present disclosure is directed to firearm bolt tail cleaning devices which remove debris from a bolt tail and polish the bolt tail via a single process. Devices in accordance with the present disclosure may be used to clean portions of bolts for gas operated autoloading firearms such as the AR-15, derivatives of the AR-15 platform, the M-16, and other semiautomatic and automatic firearms.
In some aspects of the present disclosure, the cleaning device comprises a device body configured to rotatably and slidably interface with a bolt tail via a plurality of cleaning arms. The plurality of cleaning arms extend inward toward a centerline and define a cleaning slot. The bolt tail may be inserted into the cleaning slot. The bolt and the cleaning device may then be rotated with respect to one another about a common centerline, causing the cleaning arms to remove debris from the bolt tail. The cleaning arms, when the device is injection molded, comprise 15-40 percent by weight of an abrasive material, such as glass fiber, which facilitates both debris removal and polishing of the bolt tail surface. Debris exits the cleaning device via debris removal channels defined by the radial spacing of the plurality of cleaning arms.
Further features and advantages of the devices and systems disclosed herein, as well as the structure and operation of various aspects of the present disclosure, are described in detail below with reference to the accompanying figures.
The features and advantages of the present disclosure will become more apparent from the Detailed Description set forth below when taken in conjunction with the drawings in which like reference numbers indicate identical or functionally similar elements.
The present disclosure is directed to firearm bolt tail cleaning devices which remove debris from a bolt tail and polish the bolt tail via a single process. Devices in accordance with the present disclosure may be used to clean portions of bolts for gas operated autoloading firearms such as the AR-15, derivatives of the AR-15 platform, the M-16, and other semiautomatic and automatic firearms.
Referring now to
In gas-operated autoloading systems like those found in the AR-15, gas operated firearms extract spent casings and load a new cartridge into the chamber or otherwise prepare the cartridge for firing by harnessing energy from high pressure gases generated during firing. High pressure gas is siphoned off from the barrel and injected into a bolt carrier assembly 100. Bolt carrier assembly acts as a piston and includes a bolt carrier 104 and a bolt 102. The bolt comprises a bolt tail 106. The high pressure gas impinges upon bolt tail 106 at bolt tail surface 202 (shown in
Referring now to
In order to efficiently transfer the energy contained in the high pressure gas to other portions of bolt carrier assembly 100, bolt tail 106 includes a bolt tail top 206 and a bolt tail body 106. In an aspect, bolt tail top 206 and bolt tail body 204 have circular cross sections. Bolt tail top 206 has a concave curvature, having a larger diameter at a first end which curves down to a smaller diameter at a second end where bolt tail top 206 connects with cylindrical bolt tail body 204.
In order to ensure proper functionality and reliability, debris must be removed from both portions of bolt tail 106 and both portions must be polished. The high pressure exhaust gases which power the gas-operated autoloading process are combustion gases. The gases comprise vaporized metals, carbon, incomplete combustion products, oxides, particulates, and other impurities contained in the ammunition propellants. These materials impinge on bolt tail 106 causing debris to build up, which must be regularly removed in order for the firearm to continue to function properly.
The profile of bolt tail 106 may vary, depending on the overall configuration of the firearm and bolt 102. In an aspect, bolt tail top 206 may have a gradual slope from the narrow radius of bolt tail body 204 to the larger radius of the remainder of bolt 102. In another aspect, bolt tail top 206 may be steeply sloped. In yet another aspect, bolt tail top 206 is not sloped. Rather, bolt tail top 206 may be oriented at a right angle or near-right angle to bolt tail body 204.
Referring now to
Bolt tail cleaning device 300 includes a unitary device body 302 and a cleaning slot 401 (shown in
Device body 302 is a substantially rigid member including a plurality of cleaning arms 304 (labeled as cleaning arms 304a-d in
Cleaning arm 304 removes debris from bolt tail 106 via scraping action. In an aspect, cleaning arm 304 has sharp edges positioned adjacent to and interfacing with bolt tail surface 202 when bolt tail 106 is placed in cleaning slot 401. Cleaning arm 304 is constructed of a material comprising an abrasive material such as glass fiber. The abrasive material may contact bolt tail surface 202 and further facilitate removal of debris and polishing of bolt tail surface 202 when the major portion of the debris has been removed.
The plurality of cleaning arms 304 form a plurality of debris removal channels 306 (labeled as channels 306a-d in
Device body 302 is a substantially rigid, cylindrical member having a radius chosen to facilitate hand rotative operation of cleaning device 300. Device body outer surface 310 is configured to facilitate operation of cleaning device 300. In an aspect, device body outer surface 310 further includes a plurality of ridges 308 (labeled, for clarity, only as ridges 308a-b in
Bolt tail cleaning device 300 removes debris from bolt tail 102 via slidably interfacing with bolt tail 102. Once in place, bolt tail cleaning device 300 may be rotated and moved lengthwise along bolt tail 102, thereby removing debris from bolt tail 102 via rotatably and slidably interfacing with bolt tail 102. In an aspect, cleaning arms scrape debris from bolt tail surface 202 and polish bolt tail surface 202 via such movement. Friction forces between debris and bolt tail surface 202 also facilitated removal of debris and polishing.
Referring now to
Cleaning arm 304 (labeled, for clarity, only as cleaning arm 304a in
Inner wall portion 504 may be configured to conform to portions of bolt tail 106 when bolt tail 106 is inserted into cleaning slot 401. In an aspect, inner wall portion 504 is concave, convex, or flat. In another aspect, inner portion may be ribbed, ridged, or have a rough texture in order to facilitate removal of debris from bolt tail 106. Inner wall portion 504 is worn down during operation of cleaning device 300, causing inner device to more closely conform to bolt tail 106. That is, inner wall portion 504 may initially be configured as a flat surface. Via frictional interaction with bolt tail 106 during operation of cleaning device 300, portions of inner wall portion 504 are worn away, yielding a concave surface.
Cleaning device 300 along line 501 is shown in
Middle portion 508 is configured to conform to a portion of bolt tail body 204. Middle portion 508 may be curved to conform to a portion of bolt tail surface 202. In an aspect, middle portion 508 has a concave curvature.
Referring now to
In order to utilize cleaning device 300, bolt tail 106 is inserted into cleaning slot 401. The centerline of bolt 102 is aligned with the centerline of cleaning device 300 and bolt tail 106 is slidably inserted into cleaning device 300 at cleaning slot 401.
Referring now to
As shown by rotative action broken line 701, bolt 102 and cleaning device 300 may be rotated relative to one another in order to remove debris from bolt tail 106 and polish bolt tail 106 in a single repetitive process. Bolt 102 and cleaning device 300 also move laterally relative to one another in order to remove debris and polish portions of bolt tail 106.
Cleaning arms 304 are constructed of a variety of materials. In order to facilitate cleaning and polishing of bolt tail 106, cleaning arms 304 in preferred aspects of the present disclosure are constructed of a rigid material which comprises an abrasive material. The abrasive material facilitates polishing action.
The abrasive material may be a fibrous material such as glass fiber, fiberglass, carbon fiber or graphite fiber. In an aspect, cleaning device 300 is constructed of a polymer (e.g., an injection moldable polymer) which contains 15-40 percent by weight of glass fiber. If the cleaning device were to be made by casting in a mold, the abrasive material may be a granular material such as sand, grit, silicon carbide, aluminum oxide, metal shavings, glass shards, and the like. Also, the percent by weight of the abrasive may be reduced to 5-20 percent in such a cast cleaning device.
During operation, portions of the polymer making up cleaning arm 304 is removed by frictional interaction and other erosive or ablative forces. Such removal exposes the abrasive material, facilitating debris removal and polishing of bolt tail 106. For example, where the abrasive material is glass fiber, the polymer is worn away during use exposing more and more of the embedded glass fiber. Cleaning arm 304 wears in the general shape of bolt tail surface 202 being cleaned. As this happens the exposed glass fibers act as thousands of abrasive surfaces that not only scrape away debris but also polish bolt tail surface 202. The nature of such glass fiber and polymer construction allows cleaning device 300 to be used in conjunction with cleaning solvents and compounds to enhance the cleaning operation.
While various aspects of the present disclosure have been described above, it should be understood that they have been presented by way of example and not limitation. It will be apparent to persons skilled in the relevant art(s) that various changes in form and detail can be made without departing from the spirit and scope of the present disclosure. The present disclosure should not be limited by any of the above described aspects, but should be defined only in accordance with the following claims and their equivalents.
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