I use it a lot in 45 Colt. Also in 44 spcl and 480 Ruger and 475 Linebaugh.
Is it a bit dirtier than some other powders? Yes, but so what. All powders are dirty to one extent or another. I expect you are going to clean your guns at some point anyway. Right? And before you have shot so many thousands of rounds that your gun locks up. Right? HS6s benefits outweigh it being a little dirty.
Look up Brian Pearce in Handloader and John Linebaughs site to get some recommendations for HS6
Byron
