Abstract: A safety mechanism in which a striker on the hammer can hit the firing pin to discharge the firearm only when the trigger is intentionally pulled and the pull on the trigger is maintained. The striker can move on the hammer and is pushed to the firing position by a weak spring. A safety arm associated with the trigger, pushes the striker to a mis-aligned position in which it cannot hit the firing pin. If the hammer is released accidently by inertial forces, such as dropping or bumping the firearm, the safety arm engages and mis-aligns the striker as the hammer falls, before the striker arrives at the firing pin. Pulling the trigger withdraws the safety arm, but the pull must be maintained until the hammer falls, in order to discharge the firearm.