In accordance with the first exemplary embodiment a semi-automatic M-4 type firearm is provided. The firearm comprises a receiver and a reversible safety selector. The receiver has a right side and a left side. The reversible safety selector is rotatably coupled to the receiver and comprises a shaft with a user selector member at one end. The user selector member is adapted to allow a user to move the reversible safety selector relative to the receiver. The reversible safety selector is adapted to be mounted to the receiver in a first position with the user selector member located on the right side of the receiver. The reversible safety selector may be mounted to the receiver in a second position different from the first position with the user selector member located on the left side of the receiver.