Someone has commented that 4064 seems faster than it originally was. I believe that’s been confirmed elsewhere as well, notably in an article I read about jack O’Connor’s pet 270 load using enough 4064 to cause big trouble of one attempted to replicate it today. Same goes for h4831. It’s faster than the milsurp powder it started out as. And of course people have got into trouble interchanging imr and hodgdon powder (4350, 4831, 4198) when they’re not the same thing.