Nothing in my manuals about using HS6 with a bullet that heavy in those particular cartridges. The closest it gets is for use with a 215 Grn jacketed in 44Spl and a 240 jacketed in 44Mag.
As a side note...I found it interesting that my Speer Manual says to use magnum primers with that powder, in those cartridges, regardless of the charge or bullet weight being used. I don't use HS6 so I can't say why that is, nor can I say why I can't find any heavy-ish LSWC bullet loads listed...but is does tell me that something unusual is going on there relative to my experience with using what I can only call "more-traditional" powders for loading the .44's that I've had.
If you don't mind a suggestion....T'were it me, I'd be looking for a more-proven powder which I could easily find verifiable loading info for...say, Unique and/or 2400, depending on how fast ya want to go.
DGW
