Herco's worth a look for Magnums
I liked Herco in my .357 Magnum. Just check the books and see how it compares with Unique and 2400 and 296.
Winchester's velocities on 296, BTW, are about 300-400 fps optimistic IME. I could never, for example, get better than about 1450 fps with 125-gr bullets, using 3.5 grains MORE than Winchester said to load. Speer #10 or #11, IIRC, said it was okay, but #13 has that load backed off a full grain now...
Alliant's published velocities are only 100 fps off, IME. Same direction.