For cast boolit loads in my .303 Lee Enfields I like the NOE 316299 GC over IMR4227 or Unique for moderate cast boolit loads/velocities and the Mihec 316410 over 700X which I am out of now so have to find another fast powder for that one. The 316410 is a PB boolit so I don't push them too fast but that HP vapourizes a 1 gal. water jug out to 50 yards and still does a good number on it at 100 yards!
Longbow