I have done dozens of trigger jobs on S&W. I love working on them. I always take it all apart, pollish every part, and then try several different springs. You want to make sure that you have the right springs to make the hammer fire the primer. Also how light do you want it. It gives me the shivers thinking about some of the work I done on model 19s and 29s. With a double action you want it to be smooth as glass when squeezeing the trigger and it goes off without you knowing, but when the hammer is pulled back and locked you want it to go off when your finger wants it to, not when the trigger wants to go off when your finger is on it. This is a "X" frame the largest of S&W revolvers. Make sure that you get a GOOD Smith to work on it, especially since the large caliber. You don't want it going off before you want because the pistol will FLY out of you hand)(s) if you are not ready.