I've been using cast for all my .44Mag reloading so far. I haven't done any H110 loads yet but the ones I've done with 2400 and 4227 have not produced any leading that I can tell. Mind you I've been mixing in a few rounds of jacketed as well which, if rumours are true, tends to wipe away any leading. Bullets for this are 240 grain RNFP's.
I strongly suspect that leading isn't as big a risk as some think. After all Elmer Kieth did much of his high power shooting using the cast Keith bullets. And unless they use a gas check it apparently wasn't an issue.