A firearm with safety mechanism in one embodiment comprises a receiver, a trigger-actuated firing mechanism with movable trigger operable to discharge the firearm, and a safety mechanism configured to arrest the firing mechanism. The safety mechanism is movable between a first position preventing movement of the trigger and a second position allowing movement of the trigger for discharging the firearm. In one embodiment, an elongated stock bolt attaches a buttstock to the receiver. The stock bolt passes through a portion of the safety mechanism to engage the receiver. This allows an operating button of the safety to be ergonomically mounted on a top surface of the firearm above the stock bolt. In one implementation, the firing and safety mechanisms may each be operably mounted in a fire control module disposed in the receiver and removable therefrom as a separate self-supported unit.