A semiautomatic firearm and firearm firing mechanism includes a bolt assembly having a bolt body coupled to a locking head for imparting a dwell in the sequence or process of bullet casing ejection, reloading, and re-cocking sequence during firing of the firearm. The locking head and bolt body rotate relative to one another as they translate longitudinally relative to one another, owing to corresponding engagement members. The locking head includes an additional engaging member for engagement with a corresponding engaging member along an inner surface of a fire control housing that houses the firing mechanism, so that the rotation and longitudinal translations of the locking head are performed in a controlled manner, which further controls the movement of the locking head and the bolt body relative to one another. A striker is released by a sear, which is coupled to a trigger, to initiate the firing and reloading/re-cocking sequence.