The compositions proposed contain, as their main constituents,(a) a diorganopolysiloxane with triorganosiloxy groups as terminal groups, the organic groups being hydrocarbon groups which may be halogenated,(b) the reaction product of a diacylated diorganotin compound with a disilaalkane containing, per molecule, at least two monovalent hydrocarbon groups which are bonded to silicon via oxygen and may optionally be substituted by an alkoxy group, or with an oligomer of such a disilaalkane,(c) an organosilicon compound containing, per molecule, at least one amino or amino group bonded to silicon via carbon,(d) optionally, a filler and(e) optionally, a disilaalkane and/or silane containing, per molecule, at least three monovalent hydrocarbon groups which are bonded to silicon via oxygen and may optionally be substituted by an alkoxy group, or an oligomer of such a disilaalkane and/or silane.