I picked up my pretty revolver today and right off the bat am having light hammer strikes. One to three 550 box federals were failing to fire but do eventually fire. Took the sideplate off and it was very dry so I oiled it and tried again, still light strikes. Swapped out the mainspring with some spares, no improvement. Had a few long strain screws in my parts box and tried one tight with the grips that were on the gun and the trigger was horrible. Got to looking and those grips have a huge internal boss for the grip screw. That was putting the mainspring into a big bind with a longer strain screw screwed in tight. I temporarily replaced the grips with a set of butt boot grips that almost fit. I also removed the long blued strain screw with the shorter factory screw with a fired primer between the screw and mainspring. Eureka! Just fired 2 cylinders worth with no problems. Thinking a combination of not enough strain screw pressure and grips being in the way. I might try to replace the mim stuff, wondering if a solid steel hammer would make a difference. Just ordered a model 17 hammer off ebay, we'll see.