Abstract: A high specific gravity composition suitable for use as a lead-substitute, especially for firearms ammunition and angling weights, comprises:(i) a polymer matrix comprising:(a) at least one rigid thermoplastic polymer component, e.g. polypropylene, polystyrene, etc. and(b) at least one elastomeric thermoplastic polymer component, e.g. various polystyrene-based copolymers; and(ii) dispersed in the polymer matrix particles of a high specific gravity weight material having a density and present in an amount such that the composition has a specific gravity of greater than one, preferably a specific gravity in the range 8 to 12.The high specific gravity weight material is preferably tungsten powder.