I have a ongoing e mail with Wolff springs. They supply SW with the reduced mainspring for the PC revolvers. The JM is really a Pro series not a PC but regardless, I put the Type 2 reduced mainspring in it and it barely made a dimple in the primer, I knew as soon as I installed it and dry fired it that it was too light and would not work.
My PC 327, 357 went back to SW twice for light strikes, crane, firing pin and new mainspring.
