I was given an 8lb can of win 571 powder. Anybody familiar with the powder? I like to use it up. I shoot 40s&w, 357mag, and 12ga trap and skeet. I understand HS-7 is also the same powder. Its only in the older loading books.
I use it for high velocity 20 gauge 1 oz. loads. It's considered relatively slow burning for shotgun shells.