Hodgdon HS-6 doesn't have a Winchester twin (different VoluMetric Density), but it is VERY close to the same burn rate as W-540.

HS-7 and W-571 are the same VMD according to Lee data and are adjacent on the burn rate scale, so probably interchangeable. I have not seen much info recently about HS-7, they may be taking it out of circulation.

I have not yet taken many trial loads of HS-6 to the range, so I'm not going to offer any advice. The Hodgdon Reloading site <http://www.hodgdonreloading.com/data/pistol> should give you the same good information generously supplied by Swifty. HS-6 is fine-grained and measures well.

“You must endeavour to enjoy the pleasure of doing good. That is all that makes life valuable.”
Robert E. Lee, in a letter to his invalid wife.