I've tried a bunch of different loads in the .45-70, but one of the best shooting is:
Starline brass
CCI 200 primer
H322, 47 grains
Beartooth bullets Piledriver Jr (advertised as 425 grains, actual weight 436 grains)
OAL @ 2.550"
Yields 1679 fps in my Guide gun, recoil is somewhat sporty off the bench, but accurate...and penetrates.
If a T-Rex escapes the Zoo, substitute the PJ jr for the Piledriver (525 grain, actual weight 540 grains), cut the charge back to 41 grains. Runs 1540 fps and really, really penetrates.
