I'm mixing them aren't I!?
The slugs are 430gr and the powder charge is 19gr, ideally I want subsonic but is that too low?
I know with the 9mm the danger from too low a charge is the bullet staying in the barrel and the next one following it up, but when you are single loading and checking this should be less of a risk. The big question is would the pressure spike if the slug failed to leave the barrel?
All hypothetical til I find out more numbers