A weapon system for firing a round from a belt of rounds, the weapon system comprising: a receiver; an operating group configured to operate the weapon system through a charged condition, a firing condition, and a recoil condition, the operating group comprising a barrel extension at least partially housed within the receiver and arranged to axially translate relative to the receiver; an operating rod (op-rod) assembly at least partially housed within the barrel extension and arranged to axially translate within the barrel extension between the charged condition, the firing condition, and the recoil condition; and a bolt assembly coupled to the op-rod assembly and at least partially housed within the barrel extension and arranged to axially translate within the barrel extension between the charged condition, the firing condition, and the recoil condition; a barrel coupled to the barrel extension and defining a chamber and a bore; a gas accelerator 500) with a first end coupled to the barrel and a second end coupled to the op-rod assembly; a buffer assembly comprising a self-centering spring and a hydraulic piston assembly having a first end coupled to the receiver and a second end coupled to the barrel extension; and a feeder coupled to the receiver and configured to provide the round to the operating group; wherein the op-rod assembly and the bolt assembly are interlocked such that the bolt assembly is limited in axial movement by the op-rod assembly to provide a redundant containment of the op-rod assembly and bolt assembly within the barrel extension, and wherein preferably the op-rod assembly comprises at least two redundant locking cams to force the bolt assembly into a locking position; wherein the weapon system further comprises a firing pin arranged on the bolt assembly; characterised in that, in the firing position of the firing cycle, a forward portion of the op-rod assembly contacts the firing pin to actuate the firing pin into a primer of the round. a receiver; an operating group configured to operate the weapon system through a charged condition, a firing condition, and a recoil condition, the operating group comprising a barrel extension at least partially housed within the receiver and arranged to axially translate relative to the receiver; an operating rod (op-rod) assembly at least partially housed within the barrel extension and arranged to axially translate within the barrel extension between the charged condition, the firing condition, and the recoil condition; and a bolt assembly coupled to the op-rod assembly and at least partially housed within the barrel extension and arranged to axially translate within the barrel extension between the charged condition, the firing condition, and the recoil condition; a barrel extension at least partially housed within the receiver and arranged to axially translate relative to the receiver; an operating rod (op-rod) assembly at least partially housed within the barrel extension and arranged to axially translate within the barrel extension between the charged condition, the firing condition, and the recoil condition; and a bolt assembly coupled to the op-rod assembly and at least partially housed within the barrel extension and arranged to axially translate within the barrel extension between the charged condition, the firing condition, and the recoil condition; a barrel coupled to the barrel extension and defining a chamber and a bore; a gas accelerator 500) with a first end coupled to the barrel and a second end coupled to the op-rod assembly; a buffer assembly comprising a self-centering spring and a hydraulic piston assembly having a first end coupled to the receiver and a second end coupled to the barrel extension; and a feeder coupled to the receiver and configured to provide the round to the operating group; wherein the op-rod assembly and the bolt assembly are interlocked such that the bolt assembly is limited in axial movement by the op-rod assembly to provide a redundant containment of the op-rod assembly and bolt assembly within the barrel extension, and wherein the weapon system further comprises a firing pin arranged on the bolt assembly; characterised in that, in the firing position of the firing cycle, a forward portion of the op-rod assembly contacts the firing pin to actuate the firing pin into a primer of the round.