Back in the "day" (which was 35 years ago), I was a pretty fair revolver shooter. I would take my 4" Model 19 and a box of .38 Special wadcutter reloads (148-grain hollow-bases over 3.5 grains of Bullseye) to a 25-yard indoor range two evening a week and try to put all 50 in the black of a standard 25-yard pistol target while shooting one-handed offhand. I did it twice and often got 47 or more in the black. In PPC matches back then, I did well with that M19 or my 6" Python. Trust what these guys are telling you about trigger control!

With regard to the POI of different bullet weights, I had an 8-3/8" Model 14 I used occasionally for groundhog hunting when the hay or alphafa was high. My bullet of choice for that hunting was a Sierra 110-grain hollow cavity but even with the rear sight up as high as it would go, the gun shot below the POA at 25 yards but could be adjusted to center 148-grain wadcutters with plenty of sight adjustment remaining. S&W sent me a higher rear sight blade and that could be adjusted to work with both bullet weights. So yes, light/faster bullets shoot lower.

Ed