My preferred target load is 3.2 gr of Red Dot under a 158 gr LSWC. It shoots well in my 2 1/2" Model 66 and 686+, 3" Model 19. 4" Model 10 and 4" Model 15, 6" Model 19, 6" Model 66 and 6" Security Six.

Hornady listed a starting load at 2.6 gr and the max load at 3.9 gr with the 158 LSWC, so 3.2 is pretty middle of the road.