Abstract: An adjustment mechanism for a restrictor bar in a die construction of the type in which such restrictor bar is movable into and out of the internal flow path of the die so as to regulate extrusion of material therefrom. The restrictor bar movement is in axial direction and is accomplished by means of axially restrained, rotatable spools connected to threaded ends of studs in turn extending through the die body and fixedly attached to the restrictor bar. Each of the spools includes a breakable segment to cause the spools to break prior to possible stud overstressing. The spools or portions thereof may be easily replaced at a position located outside of the die and accordingly eliminates die down time.