Abstract: A mould for use in injection moulding containers, for example, comprises a pair of mould parts movable between open and closed positions and which define between them a mould cavity, co-operating frusto conical locating surfaces being provided on the mould parts for determining their relative radial positions with the locating surface on one of the mould parts being radially adjustable relative to the portions of the mould parts which define the cavity. The adjustable locating surface may be provided on a locating ring which is preferably divided into a plurality of segments, each of which is separately mounted on the mould part and individually adjustable in the radial direction by a respective screw.