Saujager--I hunt with Sharps rifles using black powder and paper patch bullets. In a 45-90 using 88 grains of 2f and a .440 diameter bullet that weighs 530 grains cast from pure lead, I have shot completely through every deer I have ever shot, including one from shoulder to ham, and have never recovered a bullet. I have shot completely through every hog I have ever shot with this load, again never recovering the bullet, although I have never shot a hog from end to end with the 45-90.
Using my 50-90, I have shot a hog from end to end, shooting at the animal as it went away from me at about 75 yards. The load was 100 grains of 2f and a 520 grain pure lead paper patch bullet. The bullet hit the left ham and came out between the shoulder blades, then punched a sharp, clean, perfectly round hole in the hogs' right ear. All four feet went straight out, and the hog went down instantly. The penetration was measured at 42 inches with a tape measure.
My experience is that with these longer bullets, soft lead is the way to go. The greater sectional density of the longer bullets keeps them from coming apart or deforming too badly, at least in the 1250-1325 fps range, and they have given me outstanding penetration. I have never shot an elk or buffalo, but some of my acquaintances have, and none of them have recovered a similar bullet from these animals on a side to side shot.
Shoot straight, rdnck