A fiber optic plug, suitable for multi-core fiber (MCF), is structured to hold satellite cores of the MCF in a precise angular positions so as to attain suitable alignment with satellite cores of a mating connector. The plug includes features to permit a ferrule holding the MCF to move longitudinally relative to the connector's housing, so that a spring may control a mating force to an abutting ferrule of a mating connector. The ferrule may be held by ferrule barrel having splines projecting away from an outer peripheral surface. The splines may slide longitudinally within notches of the connector housing or a strength member attached to the connector housing. The notches and splines have a tight tolerance, so that the satellite cores remain in a desired, set angular position.