Abstract: A firearm assembly has a lower receiver frame having an upper surface defining a horizontal plane, a hammer pivotally connected to the frame, a sear pivotally connected to the frame and movable between a retention position operable to restrain the hammer and a release position operable to enable striking motion of the hammer, an elongated link having a planar form overlaying the upper surface of the frame, the elongated link having opposed major upper and lower surfaces, a forward end, and an opposed rear end, and movable between a link forward position and a link rearward portion, the link forward end having a bolt engagement element, the elongated link having a sear engagement element protruding away from at least one of the upper and lower surfaces, and the sear having a lateral extension operably engaged by the sear engagement element.