Abstract: A vortices-activated muzzle stabilizer (2) for a gun, which muzzle stabiliser (2) comprises a cylindrical body (4) having a main vent slot (6) which defines a main gas deflection area and which deflects the gases in the form of gas vortices, a balancing slot (12) which extends at 90 degrees to the longitudinal axis of the body (4) and which is positioned opposite the main vent (6), a barrel connecting bore (14) for affording a connecting passage between the muzzle stabilizer (2) and the barrel of the and a gas exhaust aperture (20) which is positioned at a downstream end (22) of the body (4).