Abstract: A weapon system comprising a receiver, a barrel, a bolt, a barrel extension, a bolt carriage, and a toggle assembly. The barrel may have a longitudinal axis. The bolt may be spaced a distance from a rearward end of the barrel along the longitudinal axis of the barrel. The barrel extension may be attached to the bolt and connecting the barrel with the bolt. The barrel extension and bolt may be adapted to move linearly with respect to the receiver in a direction parallel to the longitudinal axis of the barrel. The bolt carriage may be movable relative to the bolt between an ammunition loading position and a firing position. The toggle assembly may be adapted to drive the bolt carriage between the loading position and the firing position in response to movement of the barrel extension and bolt relative to the receiver.