Abstract: A base for locking and supporting a cartridge loading press and an operator, which can be easily and quickly reconfigured from a storage configuration to a working configuration, and vice versa. The base includes a frame, an operator support seat secured to the frame, a loading press supporting platform secured to the frame at a location vertically higher than the seat, a ring secured to the frame below the supporting platform, and a detachable cross member. In the storage configuration, the detachable cross member is detached from the frame and the effective frame width is reduced to seven inches, which permits the base to be stored under a bed. In the working configuration, the detachable cross member is attached to the frame and the effective frame width is increased to stabilize the base and permit the weight of the press, base, and operator to be more efficiently distributed across the floor.