Anyone load black powder or pyrodex/777 in a 45-70 case.

70grs. of FF works for me! derf

We tried Pyrocrap and 777 in the 45-70. Pyrocrap would shoot chunks out that looked like flares and they would burn in the grass for a long time. 777 was no good, giving low velocities for the expense of the powder. Accuracy was not good either. Swiss 1-1/2 and 2f works the best. Stay with black powder. Use a wad on the powder, compress the powder with the wad and compression die and seat the bullet to touch the wad. Don't leave any air space between the bullet and powder. Adjust the powder charge and compression so you have the correct overall length for your bullet to kiss the rifling or up to .020 from touching the rifling.
Most of us do not size the brass, just taper the mouth, seat the bullet by hand and iron out the taper so the case chambers easy. This can be done in the size die by raising it so the taper is just ironed out. A very light crimp will also smooth out the brass.
Do NOT try to compress the powder with the bullet.