When I initally pulled my 640 Pro Series out of the box I was in love. That feeling only lasted until the first time I pulled the trigger. Even though this is a Pro Series gun, the trigger was abysmal (read: about average for a J-Frame). Attempting to test its weight on my Lyman trigger pull gauge was futile. I received the dreaded “overload” message; the trigger pull exceeded the gauge’s 12-lb capacity. Needing badly to lighten it, I purchased the Apex Duty-Carry Spring Kit from Apex Tactical Specialties.