170 grain in .38 Special??? You want hot or softball? 2400 is a trifle slow, but workable (if the barrel is not 2 inches) for hot loads. From there go to a manual. 110/W296... the other hot, hot... Softball/target, bullseye is the old standard. Red dot. Green Dot. W231. Trap 100. Again, you need the guidance of a manual. (Powder maker's web sites often have data that is useful. Proceed carefully, please.)
H1000? there is an approach some take with super slow mil. surplus powders. You fill the case, seat the bullet and see what you get. It is DIRTY. Lots of crud left behind. It may get the bullet off well and may not. You have to try. Full case is safe enough but not efficient and if you shoot much, lot of need for cleaning.
4895 (H or IMR) has been the cast bullet standard. 4064 is close and might do as well, but might not. Again, you need the guidance of a manual. If you want to save a tiny amount, you go with the fast large pistol, small rifle powders. "Reduced loads." 4227. 2400. 3031. luck.