Unique is my favorite med load powder in the 357 Magnum and may load some 158 gr cast and see how they shoot. Looking for a load that doesn't deafen you in the 357 mag , Like H110 or 296 has a habit of doing.
For what you are doing 5.5 grains of Unique over the Lyman 358439 HP or 358429 170 grain cast bullets work well.
The charge may seem light but it is a very good load for everyday shooting.
