Longbow sent me some of his nicely cast .678 balls, range lead IIRC, ~ 465 grains, to test in my rifled 3" 870. Loaded 10 in new 12 ga. Cheddite 3" hulls, 38 grns Alliant Steel powder, Nobel Sport 1 oz wads, 1 - 20 ga hard card in wad, a little #47 buffer, ball on top of that. Used a frangible clear plastic overshot disc and 6 pt crimp for a nice looking shell. These should be moving around 1500 fps. All from BPI.
Shot 5 each at measured 50 and 75 yds. The 75 yd target has only 4 holes as I had 1 squibb load, apparently a weak primer as all charges were hand weighed, but got incomplete combustion with one. Typical Steel powder big muzzle blast but reasonable recoil. Yanked one pretty bad at 75 yds but 1st 2 at 50 almost in same hole.
The fit was perfect in my gun as witnessed by the recovered wads in excellent shape. Hulls unmarked, ejected smoothly. Could go several more grains of powder but see little advantage to doing so. May do that and see what 100 yds looks like and shoot a few from smoothbore as well. For any size deer, hog or black bear for that matter, there is plenty of power in these loads. And I hate to admit it, but someone a lttle better behind the gun could prolly tighten these groups some.