A firearm having a permanently affixed magazine is provided, including a receiver assembly having a receiver. The magazine is for storing and feeding cartridges into the chamber of the firearm. An upper component of the magazine is permanently secured in the receiver. A lower component is rotatably attached to the upper component at a hinge or the lower component is accessible through an aperture. When the hinged lower component is open relative to the upper component, access to a cartridge cavity is provided. Alternatively, access to the cartridge cavity in the lower component is provided by an aperture in the lower component. When the lower component is closed relative to the upper component, or when the aperture is closed, cartridges may pass from the lower component to the upper component and are ready for firing. A magazine is also provided having these features is also provided.