Abstract: An injection-molding tool has at least two separate mold parts forming a set of mold cavities, and a set of runner channels extending between the mold inlet and leading melt flow to the mold cavities. The set of runner channels comprises a number of junctions, each junction dividing a downstream end of a primary runner channel extending upstream from the junction into two or more separate secondary runner channels extending downstream from the junction. A stretch of the downstream end of the primary runner has a cross section area being smaller than the cross section area of the primary runner further upstream from the junction.