Abstract:
An adjustable firearm handguard mounting system configured to facilitate setting the rotation of the handguard relative to a barrel nut and then clamping the handguard to the barrel nut using non-parallel screws.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to provisional application 62/236,970 filed on Oct. 4, 2015. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not Applicable 
       THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT 
       [0003]    Not Applicable 
       REFERENCE TO A “SEQUENCE LISTING,” A TABLE, OR A COMPUTER PROGRAM LISTING APPENDIX SUBMITTED ON COMPACT DISC AND AN INCORPORATION-BY-REFERENCE OF THE MATERIAL ON THE COMPACT DISC 
       [0004]    Not Applicable 
       STATEMENT REGARDING PRIOR DISCLOSURES BY AN INVENTOR OR JOINT INVENTOR 
       [0005]    Not Applicable 
       BACKGROUND OF THE INVENTION 
       [0006]    This invention relates generally to an apparatus for attaching a handguard to a firearm. 
         [0007]    Modern sporting rifles are popular, among other reasons, because they are highly configurable. Modern sporting rifles are generally comprised of a lower receiver and parts and an upper receiver and parts. One part on a complete upper receiver is a handguard. The handguard can be configured to serve a variety of functions including providing thermal protection, providing an attachment point for accessories, and providing a support point which does not touch the barrel near the muzzle. When certain accessories are attached to the handguard (e.g. sighting aids), the orientation of the handguard relative to the upper receiver is critical. 
         [0008]    One step of assembling an upper receiver is attaching the handguard to the stripped upper receiver. A barrel is generally inserted into an upper receiver, indexed using a locating pin on the barrel extension into a slot in the upper receiver, and secured with a barrel nut. The barrel nut may be configured to interface with features of specially configured handguards. Handguards which attach to the barrel nut and do not directly touch the barrel may aid accuracy by not introducing unpredictable harmonics caused by contact between the barrel and handguard or support. 
       BRIEF SUMMARY OF THE INVENTION 
       [0009]    The invention is an apparatus for attaching a handguard to a barrel nut. The barrel nut is textured on the outer circumference and has at least one groove on the outer surface. The handguard is configured to fit over the barrel nut. Screws threaded into the handguard against the textured portion of the nut set and maintain the rotation of the handguard while and after it is installed. Screws threaded through the handguard clamp the handguard to the barrel nut. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0010]      FIG. 1  shows the barrel nut of the invention. Shown are two grooves configured to cooperatively interact with clamping screws. Between the grooves are a series of radial holes having a flattened surface on the exterior of the barrel nut around each said radial hole. To the right of the right-most groove is textured portion of the circumference configured to interact with rotation adjustment screws. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0011]    The invention is a novel apparatus for attaching a handguard to a barrel nut. The barrel nut is configured with radial holes which reduce weight and provide an attachment interface used when tightening and loosening the nut. The barrel nut also contains texturing around a portion of the outer circumference of the nut. The texturing is spaced from the end of the nut such that when a rotation adjustment screw is threaded into the handguard, the screw contacts the texturing. The handguard is configured with at least one threaded hole configured to accept a screw to set the rotation of the handguard relative to the nut (and an upper receiver onto which the barrel nut is attached). When the handguard is attached to the barrel nut, at least one rotation adjustment screw is threaded into the threaded hole in the handguard until the desired amount of contact with the texturing on the barrel nut is achieved. In a preferred embodiment, there are two threaded holes (and rotation adjustment screws) which are neither parallel nor orthogonal. 
         [0012]    The nut is also configured to contain at least one groove. The groove(s) is spaced such that when one or more clamping screws is threaded into the handguard, the clamping screw(s) pass through the groove(s). In a preferred embodiment, the nut contains two grooves and the handguard is configured to accept two non-parallel clamping screws. The mass of the handguard is minimized, and no additional parts are required, by configuring the handguard to accept non-parallel clamping screws. 
         [0013]    The handguard is configured with a length-wise gap positioned to overlap with the barrel nut. The handguard is also configured with at least one hole on one side of the gap aligned with a threaded hole on the opposite side of the gap. The hole(s) is/are configured to accept a clamping screw. When the clamping screw(s) is/are tightened, the inner diameter of the handguard is reduced providing a friction fit between the handguard and barrel nut. In a preferred embodiment, there are two clamping screws. In a preferred embodiment, the gap does not extend beyond the portion of the handgard which overlaps with the barrel nut. 
         [0014]    The features of the apparatus are designed for the barrel to be inserted into the upper receiver, the barren nut threaded onto the upper receiver, and the barrel nut then be tightened onto the upper receiver using a tool which interfaces with the radial holes in the barrel nut. The handguard is then slid over the barrel nut. The handguard is aligned as desired and the rotation adjustment screws are tightened. The clamping screws are then inserted into the handguard and tightened. Frictional force between the inside of the handguard and the outside of the barrel nut, in conjunction with mechanical locking between rotation adjustment screws and texturing on the barrel nut, prevent the handguard from rotating on the barrel nut. 
       SEQUENCE LISTING 
       [0015]    Not Applicable