I want to use Alliant Power Pro 300 MP powder for some .357 magnum loads but there is very limited info yet on this product for reload charges. Specifically I want to load 158 grain gas check LSWC and Sierra 180 grain FPJ for .357 magnum. Any links or personal experience with this powder for reloads would be great . . . been searching hours on WWW with no luck yet. Will be using these rounds in a carbine and a Super Blackhawk.