An apparatus implementable on a firearm may include a takedown pin and a pivot pin. The takedown pin holds together a rear portion of lower and upper receivers of the firearm. The pivot pin holds together a front portion of lower and upper receivers of the firearm. Each of the takedown pin and pivot pin respectively includes a head and a generally cylindrical shank extending from the head toward a distal end thereof opposite the head. The shank is configured with: (1) a first groove track extending along a longitudinal axis of the shank, (2) a second groove track parallel to the first groove track and extending along the longitudinal axis of the shank, and (3) a linking groove track extending around the longitudinal axis of the shank and linking the first groove track and the second groove track.