That was the reason they gave me also. That it could torque the hammer mechanism and you would not get the full force striking the firing pin. I have not had any problems since I installed the Bellm products. I also did not have any problems on any of my other barrels, only on the slug barrel. I do not know why this would void any warranty but maybe they replaced several recievers due to this before they found this "excuse". Other than this, I have not had any problems with their customer service. I have had my hammer extension on my Encore for 2 years now without any problems.