I'm not Junior , but i shoot quite a bit of lead bullets in my 45/70 and am just getting into BP , with the help of GregP42 and Dodds3 , both who have shot lots of BP from their 45/70s .
Not sure what to tell you as far as load data , what i do is to fill the case to about 1/8" above were the bottom of were the bullet will be when seated , then place the over-powder wad card in the case , at this point i use a compressing plug that i got for my Lee die to press the wad and powder into place .
Then i seat and crimp the bullet as i would with any smokeless round , right now i am getting just over 2" groups at 100 yards with a 405 gr. soft cast bullet . i still need to do some work and maybe add some powder to this load to get it were i want it . its a work in progress .
hope this helps .
stimpy