Dispensing system (100) for dispensing a mixture of a first component and a second component, the dispensing system comprising: (i) a dispensing gun comprising an inlet body with a first passage (121) for feeding in the first component under pressure and a second passage (121') for feeding in the second component under pressure, the first and second passages respectively comprising a closable first outlet and a closable second outlet, which may be operable by means of a handle or trigger of the dispensing gun; (ii) a static mixing nozzle, detachably connectable to the outlets of the body and provided for mixing and dispensing the components, the static mixing nozzle comprising a first section containing a first chamber and a second chamber for conducting the first and second component respectively and a second section, subsequent to the first section (in forwards flow direction), containing a mixing chamber with static mixing elements which promote mixing the first and second components and conducting the mixture to a nozzle tip serving as an outlet for the mixture. According to the invention, at least one of the first and second chambers of the static mixing nozzle contains a series of static backflow prevention elements, arranged for hindering backflow of the respective component within the respective chamber.