Numrich arms was,probably still is,selling a kit to upgrade the old style feed throat to the new style ,it includes the new style spring,feed throat and other involved parts,I don't remember if the new spring will work with the old throat,I don't think so,if you can order the kit and solve your problem and possibly future problems.If you go to Marlin owners,Marlin collectors,or rimfire central somebody else will help answer that question.
