I bought an L&R Manton lock a few years ago and the main spring broke very early in my build . . it was an older lock and so I called them and they sent me a new forged spring that is improved. It took a little filing, but not much. L&R was easy and helpful then . . . I assume they still are. When my build is done I may file the spring a little to weaken it as it's a beast. . . but I may not. . . not sure yet, I've only "fired" it when inletting the triggers and with a wood block in the cock.