A locking core plug includes an upper plate, an insertion portion extending outward from the upper plate and forming an outer perimeter, and a locking mechanism positioned within the outer perimeter of the insertion portion. The locking mechanism includes a rotating member, a plurality of locking arms having a first end connected to the rotating member and a second end extending outward toward holes in the outer perimeter, and a plurality of guides fixedly mounted to the upper plate. Each guide engages a corresponding locking arm to convert the circular movement of the first end of the arm as rotating member rotates into a generally linear movement of the second end between a release position retracted toward or within the outer perimeter of the insertion portion and a locking position extended outward from the outer perimeter of the insertion portion.