Ok. I have nothing for that357 Magnum 180gr hardcast...duplicating BuffaloBore load...
K&K has been one of the more reliable powder suppliers near Buffalo, in my experience. I'd definitely check them out.I'm pretty sure I have at least a pound if you care to take a ride to Buffalo. I'm sure I saw a few pounds of it at K&K Guns in Warsaw, N.Y. a few weeks ago. It would be worth calling them if you need it. You might find it at Ken's in Attica too. Again, give him a call. Closer to you, there's Ammo Bee and Genessee Valley Shooters. I would try both of them.