I've ordered a Lee mould from Graf's.
Forgive my ignorance, but I don't see the logic that lead bullets shouldn't be fired through barrels with polygonal rifling. A cursory search of this website and other gunboards reveals that other shooters are using cast bullets in this gun, as well as Glocks. And we all know that, if it's on the internet, then it's true!
Seriously, why would a hard cast bullet be problematic? On a range outing, I typically shoot about 100 rounds per gun, and then I give the bore a thorough cleaning when I get home. Leading hasn't been an issue for me. Of course, I will find out soon enough whether that continues to hold true and will duly report back.