The Loads below utilize Standard Winchester Small Pistol Primers, any regular .357 Magnum Brass, and were Chronographed in a 4 inch Colt King Cobra and a 6 inch S&W 686. (No discernable difference in velocities between the 4 inch barrel and 6 inch barrel were noted.)
These loads were developed to duplicate advertised Factory Ballistics.
any 125 grn JHP
12.5 grns Alliant Blue Dot
Velocity = 1470 fps
any 158 grn JHP
10.5 grns Alliant Blue Dot
Velocity = 1250 fps
2400 is my standby powder and 14.5 grains of it behind a good 158 hard cast and/or gas checked SWC is an old standby recipe for power and safe pressure in any handgun. Blue Dot burns too fast for max efficiency from a 4" or longer gun, but is better in a snub with 125 grain bullets. 2400 is too slow for light bullets in snubbies. I've proven this to myself with my chronograph and various handguns.
If you fire a 125 grain bullet using 2400 from a 2" revolver, you will not believe the fireball. You could catch your curtains on fire in the house with it, LOL!
Lots of interesting responses! I'll have to try a couple of these recipes. For target shooting 148gr WC in front of 2.8 gr of Bullseye or 3.6gr of N340 using a mag primers. For power (lots of flash and bang!!) 125gr JSP in front of 8.5gr of Bullseye with mag primers.