# US 8,739,449 B2 · High strength upper receiver system and method for modular rifle > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,739,449 B2 - Document ID: US8739449B2 - Status: Granted - Kind: B2 - Application number: 13/539,551 - Filed: 2012-07-02 - Published: 2014-01-02 - Granted: 2014-06-03 - Earliest claimed: 2012-07-02 - Applicants: Swetal K. Patel - Inventors: Swetal K. Patel - Web page: https://patentgrep.com/patent/US8739449B2 ## CPC - F41A 3/66: Breech housings or frames; Receivers - F41A 11/02: Modular concepts, e.g. weapon-family concepts - F41C 23/16: Forestocks; Handgrips; Hand guards (pump-action guns F41C7/02) - F41A: FUNCTIONAL FEATURES OR DETAILS COMMON TO BOTH SMALLARMS AND ORDNANCE, e.g. CANNONS; MOUNTINGS FOR SMALLARMS OR ORDNANCE - F41C: SMALLARMS, e.g. PISTOLS, RIFLES (functional features or details common to both smallarms and ordnance, mountings therefor F41A; projecting missiles without use of explosive or combustible propellant charge F41B); ACCESSORIES THEREFOR ## Abstract A modular rifle includes an upper receiver assembly and a barrel assembly. The upper receiver, typically fashioned from aluminum, can be strengthened by insertion of a hardened metal liner insert inside the aft portion of the upper receiver. The upper receiver liner insert is secured within the aft portion of the upper receiver assembly by engaging screw threads on the liner insert with receiving threads inside the aft portion of the upper receiver and insertion of anchor pins into the aft portion of the upper receiver. The anchor pins impinge the liner insert such that it is prevented from rotating within the upper receiver. The barrel assembly is attached to the liner insert by engaging screw threads on the liner insert with threads within a barrel nut connector sleeve. ## Claims ### Claim 1 A modular rifle system with a strengthened upper receiver comprising: a lower receiver assembly; an upper receiver assembly; a barrel assembly; and an upper receiver liner insert; the upper receiver liner insert inserted within a first portion of the upper receiver assembly and secured within the first portion of the upper receiver assembly by engaged screw threads and anchor pins, the barrel assembly attached to the liner insert; a second portion of the upper receiver assembly attached to the first portion of the upper receiver assembly; and the upper and lower receiver assemblies coupled. ### Claim 2 (depends on 1) The modular rifle system of claim 1, wherein the upper receiver liner insert is secured within the first portion of the upper receiver by engagement of screw threads on the liner insert with the screw threads within the first portion of the upper receiver. ### Claim 3 (depends on 2) The modular rifle system of claim 2, wherein the upper receiver liner insert is further secured by anchor pins inserted into the first portion of the upper receiver and impinging the liner insert. ### Claim 4 (depends on 1) The modular rifle system of claim 1, wherein the upper receiver liner insert is fashioned from hardened metal. ### Claim 5 (depends on 4) The modular rifle system of claim 4, wherein the hardened metal is stainless steel. ### Claim 6 (depends on 1) The modular rifle system of claim 1, wherein the barrel assembly is attached to the liner insert by a barrel nut connector sleeve threaded onto the liner insert. ### Claim 7 (depends on 1) The modular rifle system of claim 1, wherein the second portion of the upper receiver assembly is coupled to the first portion of the upper receiver assembly by means of an alignment tab and an alignment tab receptacle. ### Claim 8 (depends on 1) The modular rifle system of claim 1, wherein the rifle system is an M-16 or AR-15 style rifle system. ### Claim 9 A modular rifle system comprising: a lower receiver assembly; an upper receiver assembly having a first portion and a second portion; and a barrel assembly, consisting of a barrel and a barrel nut connector sleeve; and an upper receiver liner insert within the first portion of the upper receiver assembly; the upper receiver liner insert secured within the first portion of the upper receiver assembly, the barrel assembly attached to the liner insert, a second portion of the upper receiver assembly attached to the first portion of the upper receiver assembly, and the upper and lower receiver assemblies coupled. ### Claim 10 (depends on 9) The modular rifle system of claim 9, wherein the upper receiver liner insert is secured within the first portion of the upper receiver by engagement of screw threads on the liner insert with the screw threads within the first portion of the upper receiver. ### Claim 11 (depends on 10) The modular rifle system of claim 10, wherein the upper receiver liner insert is further secured by anchor pins inserted into the first portion of the upper receiver and impinging the liner insert. ### Claim 12 (depends on 9) The modular rifle system of claim 9, wherein the upper receiver liner insert is fashioned from hardened metal. ### Claim 13 (depends on 12) The modular rifle system of claim 12, wherein the hardened metal is stainless steel. ### Claim 14 (depends on 9) The modular rifle system of claim 9, wherein the barrel assembly is attached to the liner insert by a barrel nut connector sleeve threaded onto the liner insert. ### Claim 15 (depends on 9) The modular rifle system of claim 9, wherein the second portion of the upper receiver assembly is coupled to the first portion of the upper receiver assembly by means of an alignment tab and an alignment tab receptacle. ### Claim 16 (depends on 9) The modular rifle system of claim 9, wherein the rifle system is an M-16 or AR-15 style rifle system. ### Claim 17 A method of strengthening an upper receiver of a modular rifle system having an upper receiver assembly and a removable barrel assembly, comprising the steps of: inserting a liner insert within a first portion of the upper receiver assembly securing the liner insert within the first portion of the upper receiver assembly by engaging screw threads on the liner insert with receiving threads within the first portion of the upper receiver assembly; further securing the liner insert within the first portion of the upper receiver assembly by insertion of anchoring devices into the first portion of the upper receiver assembly; attaching the barrel assembly to the liner insert; and attaching a second portion of the upper receiver assembly to the first portion of the upper receiver assembly. ### Claim 18 (depends on 17) The method of strengthening the upper receiver of the modular rifle system of claim 17, wherein the anchoring devices are anchor pins inserted into the first portion of the upper receiver and impinging into the liner insert. ### Claim 19 (depends on 17) The method of strengthening the upper receiver of the modular rifle system of claim 17, wherein the upper receiver liner insert is fashioned from stainless steel. ### Claim 20 (depends on 17) The method of strengthening the upper receiver of the modular rifle system of claim 17, wherein the barrel assembly is attached to the liner insert by a barrel nut connector sleeve threaded onto the liner insert.