forward closed breech position in battery with the barrel and rearward open breech position, a cockable hammer controlled by a trigger, and a bolt release mechanism operably interacting with the bolt. The mechanism may comprise a user-actuated release button and spring-biased disconnect lever coupled thereto and selectively engageable with the hammer. Upon firing, the bolt travels rearward under recoil contacting and partially rotating the disconnect lever to engage the hammer, while simultaneously engaging the hammer which holds the bolt rearward. Actuating the release button fully rotates the disconnect lever to disengage the hammer from the bolt which returns to its forward position via a recoil spring to reclose the breech. A dual interlock safety in one position provided by the release mechanism prevents pulling the trigger and in another position prevents actuating the release button.