RichardAustin,
Your best bet is to shoot TrailBoss powder, unless your heart is set on Black powder(subs). It's alot of fun to shoot these TB loads. Anyway here is a link to Hodgdon Triple 7 data:
http://hodgdon.com/PDF/muzzleloading_manual_2008.pdf?CHECKBOX_1=onyou have to scroll down to the cartridge data portion.
Have fun and stay safe! Tom