How does it fail? Fail to eject of fail to close all the way? The gun uses a floating chamber to work the action. The pressure of the round is used to open the action and eject the empty. The spring in the rear is called a closing spring and the round it surrounds is called an inertia rod. Altering the spring tension on the inertia rod and it's travel will change the functioning of the action. That said, if there reamains too little resistance bolt recoil velocities will be too great and receiver damage will occur. I would be certain the floating chamber and the action are meticulously clean and proper lubed before making any changes. Did the weapon ever function light loads. Winchester abandoned this design because of functioning problems.