Patent Publication Number: US-8109196-B1

Title: Cleanout port for gas-operated firearms

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to U.S. Provisional Application No. 61/328,285 filed Apr. 27, 2010, and entitled “Hybrid Direct Impingement System allows for a cooler/cleaner upper receiver and allows the gas tube to be cleaned in the currently used AR-15/AR-10 class of weapons,” incorporated by reference herein in its entirety. 
    
    
     FIELD 
     The present disclosure relates to the field of gas operated firearms. More particularly, the disclosure relates to a gas tube configuration that facilitates cleaning of the gas tube. 
     BACKGROUND 
     Gas operated firearms, particularly weapons such as the AR-15/AR-10 class of weapons, have a gas tube that receives gas from adjacent the muzzle end of the barrel and routes the gas to utilize the gas to eject the empty cartridge and chamber a fresh cartridge. 
     As seen in  FIG. 1 , a conventional gas tube  1  has a solid distal end  2  that is solid and receives a pin  3  within an aperture  4  for attaching the distal end  2  of the gas tube  1  within a front sight/gas block  5  of the firearm. Distal end  6  of the sight  5  is solid. The gas tube, particularly the distal end  2  thereof, can become fouled and cleaning of the gas tube  1  is difficult to accomplish, requiring disassembly of the firearm and removal of the gas tube  1 . Even then, the distal end  2  of the gas tube  1  remains difficult to clean. Improvement is desired in the structure and installation of the distal end of the gas tube of gas operated weapons such as the AR-15/AR-10 class of weapons. 
     The disclosure advantageously provides a gas tube structure that facilitates cleaning of the gas tube and, particularly the distal end of the gas tube, without disassembly of the firearm or removal of the gas tube from the firearm. 
     SUMMARY 
     The disclosure relates to an improved gas tube system for a firearm of the type having a gas tube installed within a front sight/gas block of the firearm and in flow communication with a barrel of the firearm for routing a portion of the gas generated by the firing of a cartridge by the firearm through the gas tube for operation of the firearm. 
     In one aspect, the system includes a gas block having a longitudinal bore extending the length of the gas block; an elongate gas tube having an open distal end positioned within the longitudinal bore of the gas block; and a sealing member removably and sealingly positionable in the open distal end of the gas tube. The sealing member may be removed to enable the distal end of the tube to be selectively closed for operation of the firearm and selectively removed to open the distal end of the gas tube for cleaning of the gas tube. 
     In another aspect, the disclosure relates to a gas operated firearm. The firearm includes a barrel for passage of a bullet fired from a cartridge by the firearm, the barrel having an open muzzle and a port for routing a portion of gas generated by the firing of the cartridge out of the barrel through the port. The firearm also includes a gas block having a longitudinal bore extending the length of the gas block. 
     An elongate gas tube having an open distal end is positioned within the longitudinal bore of the gas block, the gas tube being in flow communication with the port of the barrel for routing a portion of the gas generated by the firing of the cartridge by the firearm through the gas tube for operation of the firearm. A sealing member is removably and sealingly positionable in the open distal end of the gas tube to enable the distal end of the tube to be selectively closed for operation of the firearm and selectively opened for cleaning of the gas tube. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further advantages of the disclosure are apparent by reference to the detailed description when considered in conjunction with the figures, which are not to scale so as to more clearly show the details, wherein like reference numbers indicate like elements throughout the several views, and wherein: 
         FIG. 1  shows a prior art gas tube. 
         FIGS. 2 and 3  show a gas tube according to the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     With reference to  FIGS. 2 and 3 , the disclosure relates to a gas tube system  10  for a gas operated firearm, such as the AR-15/AR-10 class of weapons. The gas tube system  10  is an improvement over conventional gas tube systems, such as shown in  FIG. 1 . As described previously, the conventional gas tube  1  has distal end  2  that is solid and receives the pin  3  within the aperture  4  for attaching the distal end  2  of the gas tube  1  within the front sight/gas block  5  of the firearm. The gas tube  1 , and particularly the distal end  2  of the gas tube  1 , can become fouled and cleaning of the gas tube is difficult to accomplish, requiring disassembly of the firearm and removal of the gas tube. Even then, the distal end  2  is difficult to clean. 
     With reference to  FIGS. 2 and 3 , the system  10  includes a gas tube  12  according to the disclosure and having a distal end  14  located within a front sight/gas block  16  of a firearm  18 . A port  20  within the gas block  16  places the gas tube  12  in flow communication with a barrel  22  of the firearm  18 . A portion of the gas generated by the firing of a cartridge by the firearm  18  is routed to the gas tube  12  as a bullet  24  fired by the cartridge is discharged from the barrel  22 , as indicated by the arrows. 
     The distal end  14  of the gas tube  12  is not solid like the distal end  2  of the gas tube  1 , but is open in the manner of the remainder of the gas tube  12  so as to be in flow communication with the other portions of the tube  12 . However, to enable the distal end  14  of the tube  12  to be selectively closed, in the manner of the solid nature of the distal end  2  of the tube  1 , a sealing member  30  is removably and sealingly positionable within the distal end  14  of the gas tube  12 . 
     When the sealing member  30  is installed within the distal end  14 , the sealing member  30  functions to seal the distal end  14  against passage of gas therethrough so that gas travels from the barrel  22  via the port  20  and down the gas tube  12  in a direction away from the distal end  14 , as shown by the arrows in  FIG. 2 , thus replicating the travel of gas in the conventional gas tube  1 . 
     However, the sealing member  30  may be selectively removed from the distal end  14  without disassembly of the firearm  18  or removal of the gas tube  12 , to provide a path for insertion of a cleaning tool, such as an appropriately sized brush or swab, to permit cleaning of the entire gas tube  12 , and particularly the distal end  14 , to remove powder residue and other fouling associated with the gas operation of the firearm  18 . 
     For example, the interior of the distal end  14  of the gas tube  12  may be threaded and the sealing member  30  may be provided as by a threaded fastener that may be threaded into the distal end  14  from the distalmost end thereof for sealing the distal end  14  of the tube  12  against the passage of gas therethrough. Removal of the threaded fastener may be easily accomplished as by use of a knurled head  32  or other configuration for use with a tool to turn the fastener for threading and unthreading thereof relative to the distal end  14 . 
     To be compatible with the gas tube  12 , the front sight/gas block  16  has a longitudinal bore  34  extending the length of the gas block  16  and sized to fittingly receive the distal end  14  of the gas tube  12 . The bore  34  fittingly retains the gas tube  12 , yet permits it to be slidingly removed therefrom if desired. In this regard, it will be understood that such weapons include a front gas block configured to route gas from the barrel to the gas tube. In many instances, the gas black is configured as a front sight. However, some firearms configured for use with laser sights do not configure the gas block to have a front sight function. Accordingly, as used herein, the term “gas block” will be understood to refer to a structure that routes gas from the barrel to the gas tube, with or without additional structure to configure the gas block as a sight. 
     Accordingly, it will be appreciated that the gas tube system  10  advantageously facilitates cleaning of the gas tube and, particularly the distal end  14  of the gas tube  12 , without disassembly of the firearm  18  or removal of the gas tube  12  from the firearm  18 . 
     The gas tube system  10  may be installed on a new or existing firearm preferably using a newly manufactured gas tube and a newly manufactured gas block having the described structure. Alternatively, it will be appreciated that the existing gas tube and gas block of a firearm may be modified by drilling the gas tube and the gas block to provide the structure of the disclosure. 
     The foregoing description of preferred embodiments for this disclosure has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments are chosen and described in an effort to provide the best illustrations of the principles of the disclosure and its practical application, and to thereby enable one of ordinary skill in the art to utilize the disclosure in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the disclosure as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.