by rc42 » 11 Feb 2021, 10:12 pm
If you have a look at the ADI loading tables the figures are largely the same for pistol or rifle loads for 357 Magnum, the peak pressure figures are the same for both and the factory loads can be used in either so that's a good starting point.
Rifles can take advantage of slower burning powders as the projectile spends longer in the barrel so you can get a higher muzzle velocity if that's what you want, however, the same loads will also work fine in a pistol, you'll just get a bigger fireball out of the muzzle which looks awesome when shooting at night.
Whatever powder you currently use just look up the starting load for any 357 mag firearm and start with that, then tune as you would your rifle loads. Slower burning powders that fill the case benefit from magnum primers, faster powders are fine with small pistol primers.