Fun and easy in the .45/70. Just buy Speer SWC Swaged lead pistol bullets in .451/.452" diameter and paper patch them to about .458-.460". Seemed to shoot better with a 50/50 Vaseline/Beeswax lubricant. Bullet fully expanded in picture went through a nice 8pt whitetail.
Bullets at far left are the 250 gr Speer factory pistol bullet. Next is a 325 gr .452"bullet cast in pure [close to it]lead and wrapped for the .45/70 also. Last is a factory Hornady .357 pistol bullet patched, lubed, and sized back to .360" for .35 rounds [38Spl/358 Win, etc], I forget the weight.