Abstract: A single shot rifle having a cam operated, falling breechblock firing mechanism. The firing mechanism includes a breechblock vertically movable within a housing member, and a laterally movable hammer operable to strike a cartridge. The firing mechanism further includes a pivotal breechblock link, connected to a manually operable lever, to effect vertical movement of the breechblock. Additionally, the lever is pivotal about a rotary cam member featuring three cam riding surfaces to operate an ejector mechanism for extracting spent casings from a breech, and to allow manual insertion of a fresh cartridge into the breech.