The new Lyman cast Bullet manual has loads for 357 mag rifle.
Now... Before you purchase your gun.
Decide what you want to do with it.
If you want a all around shooter look into the Rossi M92
If your looking for a hunter. I.E. Deer or Hogs.
I suggest looking into a Marlin.
The Rossi has a 1 in 30 twist rate while the Marlin has a 1 in 16 twist rate.
I have a Rossi and it has difficulty with heavy bullets.
Bigger than 158 gr. The 180rnfp's I wanted to take a deer with would not group to a 12 inch paper plate at 50 yards.
Just wont stabilize the big ones.
125gr, I can cut the bull out at 100 yards shot after shot.
So if you want a easy time with the heavies look at the 1 in 16 twist.