WW571 (the same powder as Hodgdon HS-7) is pretty slow burning for standard .45 Colt loads.
It's more suitable for magnum loads like the .41/.44 Mag or the .454 Casull class cartridges.
http://data.hodgdon.com/cartridge_load.asp
Hodgdon doesn't list any loads for the powder under either name in their online manual.