Abstract: A breech plug for sealing the breech end of black powder guns is constructed of two pieces. The first piece is an inner plug which threadedly engages internal threads at the breech end of the barrel and creates a bore seal. The second piece is an outer housing adapted to mate with the inner plug and to effect alignment with the barrel flat sides and barrel breech end. An assembly technique utilizing this composite breech plug greatly simplifies the machining procedures and reduces the cost normally associated with producing high quality black powder guns with a full hook breech plug.