>>Noted, that's something I did not know, does this apply to cast only or jacketed bullets too? <<
I got excellent accuracy out of jacketed bullets at with the old Elmer Keith load for the 1886. It was 53 grains of 3031 with a 400 grain bullet. This is NOT a load recommendation for older weaker rifles or older weaker men.
I have also gotten good accuracy from 500 grain jacketed bullets in a 45-70 but they produce too much recoil at the higher velocities.