Abstract: A firing mechanism for a firearm wherein a firing hammer is actuated by a firing spring and cam arrangement and wherein engagement between a sear and the hammer is arranged to provide a positive lock against misfire but simultaneously to provide a light trigger pull for firing in which, during the firing cycle, the hammer element moves in response to force applied to the sear only a small amount which is insufficient to bring the full force of frictional resistance of the firing spring and cam elements into play. The trigger is adjustable to facilitate attainment of the appropriate spacial relationships.