Abstract: In an air-operated plural component dispensing hand gun, including a sliding mixing and dispensing element that forms, with a pair of component inlet blocks, the valves controlling the mixing and dispensing of the plural component materials, the mixing and dispensing element includes a rearward part and a forward part which together form a mixing chamber, with admission passages for the plural components to be mixed in the rearward part and a dispensing orifice for mixed plural component material in the forward part, said mixing chamber having an enlarged portion in the rearward part.