A process for the preparation of a molded article formed of an isotactic ethylene propylene copolymer comprising providing an isotactic ethylene-propylene copolymer having an ethylene content of no more than 5 weight percent produced by the copolymerization of ethylene and propylene in the presence of an isospecific metallocene catalyst; heating the copolymer to a molten state; incorporating a nucleating agent into copolymer in an amount effective to provide a uniform shrinkage of the molded article at 48 hours molding of the at least 85% as determined by the differential in transverse and longitudinal shrinkage at the 48 hour mark; extruding the molten copolymer into a mold cavity; cooling the copolymer within the confines of the mold cavity to solidify the copolymer and form the molded article which is then retrieved from the mold cavity.