A plastic preform (10) for forming blow molded plastic containers wherein the inside wall face (17) of the tubular body portion (14) adjacent the bottom structure (15) and extending onto the bottom structure (15) has a plurality of faces (19) with terminal portions thereof (19a). Scallop-shaped segments (20) are provided connecting the terminal portions (19a) of each face to initiate deformation prior to deformation of the faces and thereby have an increased rate and degree of orientation.