A few days ago I ran across a nice 6" 629-1 for a good price. The gun was in time so I bought it. I took off the grips and noticed it had a light trigger because the strain screw was slightly backed off a couple of turns.

Well, I didn't look close enough or didn't put enough pressure on it when checking for push-off. It would push off with about 6 or 7 lbs of thumb pressure. After taking it apart I could see where the single action notch on the hammer had been stoned very low. A couple of strokes with a #4 Swiss cut file with a safe edge and then a few strokes with a medium India stone on the hammer and a couple on the trigger resolved that and now a 15 lb weight can't push it off. So far, so good. After reassembly with a tight strain screw (.480" so I know it hasn't been shortened), the trigger was dragging and not completely returning. A little blue dye showed the hammer block to be binding between the hammer and frame, preventing the rebound slide from returning unimpeded. I figure this was the main reason for backing out the strain screw to take off some pressure from the hammer. A few strokes with the Medium India stone to thin the hammer block provided enough clearance for it to let the rebound slide return freely and still have enough thickness to prevent the firing pin from protruding.
I really hated to stone the original flash chromed parts but I didn't have much choice, they were not safe. And getting new ones....... I'm assuming the flash chromed parts are case hardened too and know that I probably removed what remained after whoever had originally screwed this thing up.
I'm wondering if they tossed the original hammer block and it was replaced with another later.

I guess the moral of this story is BEWARE USED GUNS! It will be okay to shoot at the range but I would hard pressed to trust it with my life.

I'd like some observations from anybody that run into similar symptoms.