Firearm receiver assembly
An upper receiver assembly for a firearm having an upper receiver with an integral barrel nut, a handguard assembly and a barrel nut assembly with a barrel and lock nut is provided. The barrel is received by the upper receiver and is secured directly to the upper receiver using the lock nut. The upper receiver also includes an integral handguard mounting member to which the handguard assembly may be directly attached. The upper receiver assembly allows the user to attach both the barrel and handguard assemblies directly to the upper receiver, independently of one another.
1. An upper receiver assembly for use with a gas operated firearm having a gas operating system, the upper receiver assembly comprising:
a barrel having an annular flange about its back end;
a lock nut fitted around a portion of said barrel;
an upper receiver having a front end having an integral receiver extension extending therefrom, said receiver extension substantially shaped like a circular, elongated cylinder with a top portion of cylinder wall removed, a forward end of said receiver extension having an incomplete circular opening with a threaded interior, and wherein a forward face of upper receiver includes an opening in communication with a channel that runs approximately parallel to a longitudinal axis of said upper receiver assembly, wherein said opening has a forward end and a rearward end, said opening being wider at said forward end, gradually tapering down in diameter along its length towards said rearward end; and
a handguard assembly including a top segment and a bottom segment, said bottom segment having a rearward end machined to receive and be secured to the receiver extension by fasteners configured to removably secure said bottom portion of said handguard to said receiver extension.
2. The upper receiver assembly of claim 1 , wherein a rear portion of said bottom segment is substantially cylindrical with a correspondingly cylindrical inner bore; a forward end of said receiver extension being received within said bottom segment cylindrical inner bore and held therein with a plurality of fasteners received within aligned openings in said receiver extension and openings in said bottom segment to removably secure said bottom segment of said handguard assembly to said receiver extension.
3. The upper receiver assembly of claim 1 , wherein said top segment is removably coupled to said bottom segment and restrained from movement by said bottom segment.
4. The upper receiver assembly of claim 3 , wherein said top segment comprises an upper surface comprising an integral rail portion.
5. The upper receiver assembly of claim 4 , wherein said rail portion comprises multiple rails separated by traverse grooves there between.
6. The upper receiver assembly of claim 2 , wherein said bottom portion comprises a front portion angled to reduce weight of the handguard.
7. The upper receiver assembly of claim 6 , wherein said front portion comprises two receptacles, and two pusher screws received in each receptacle, wherein each pusher screw is retained by at least one c-clip and o-ring, and wherein each pusher screw is textured and of size to be gripped and rotated.
8. The upper receiver assembly of claim 2 , wherein said bottom segment comprises a rear portion with an opening into an interior of said bottom segment, wherein said opening is generally circular in shape with an apex of said opening removed.
9. The upper receiver assembly of claim 8 , wherein said opening into the interior of said bottom segment is adjacent to a bore that defines a portion of said bottom segment's interior, wherein said bore comprises a rearward end by said opening and a forward end defined by an approximately semi-circular bearing surface.