As you look at the profile of the hammer you will note a 1/8 in., differently angled surface extending just below the surface of the hammer that strikes the firing pin, and above the cut-out section where the hammer block fits. Not sure if "hammer stop" is the correct term.
Gunsmith said its...
I experienced the same problem with my S&W 327 TRR8...very accurate, but with light primer strikes and rusulting FTFs about half the time on PMC and Golden Eagle .38 Special ammo. I tried tightening and shimming the main spring strain screw, and replaced the main spring with no success. Very...