Patent ID: 9140506
Filing Date: 2015-09-22
Classification: F41A,F41C

Abstract:
1. An upper receiver assembly for use with a firearm having a gas operating system, the upper receiver assembly comprising: a barrel assembly having a barrel, an annular flange about a back end of said barrel and a lock nut encircling a portion of the barrel; an upper receiver including a front end having a substantially cylindrical receiver extension extending therefrom, a forward end of said receiver extension having a substantially cylindrical opening with a threaded interior into which the back end of said barrel assembly is received, said front end having a bearing surface against which said annular flange of the barrel assembly rests, said threaded interior constructed to cooperate with threads on an outer surface of said lock nut so that said locknut, when threadedly secured inside the receiver extension, mounts said barrel assembly directly to said receiver extension of said upper receiver; and wherein said receiver extension is substantially shaped like an elongated cylinder with its top portion removed.