Various weights of reduced power hammer springs in one kit help you precisely tune your semi-auto pistol for the smoothest double- and/or single-action pull and proper function. KIT #26581 S&W 39/59, 439/459, 3904/3906, 5903/5904/5906, 645/745/4506, 4006/1006 - Contains 1 each 16 lb., 17 lb. and 18 lb. hammer springs. Factory spring is 20 lbs.
Various weights of reduced power hammer springs in one kit help you precisely tune your semi-auto pistol for the smoothest double- and/or single-action pull and proper function. KIT #26581 S&W 39/59, 439/459, 3904/3906, 5903/5904/5906, 645/745/4506, 4006/1006 - Contains 1 each 16 lb., 17 lb. and 18 lb. hammer springs. Factory spring is 20 lbs.