The bone, below the joint where Dan is holding the leg, to make a nice lung shot, is about 3 1/2" in diameter. Even a yearling bull calf has 2" to 2 1/2" of solid bone there. It's amazing how well that solid green bone will stop projectiles.
WW for moose is a very good idea, and is what makes the round ball better for really large game than any muzzleloading conical. Conical bullets did not replace the round ball for dangerous game until the breech loaders allowed heavy charges with hardened 'bolts'(concials). The ability of alrger bored muzzleloaders to shoot hard balls is what kept them in use long after the Lefaucheau breechloaders came into use. They were restricted in charge due to ctg. length and strength in the early days and could not surpass the lowly round ball on the truley large animals of chase.
My first moose with the .69, collected a round ball smack dab on the leg bone (about where Dan's hand is) after hitting 50 yards of willow branches. I heard the fttttttttttttttwhock of the ball's flight. That first shot was a pure lead ball, driven by 165gr. 2F. The moose was roughly 100yards away & the ball struck about 10" left of my point of aim. His rear legs sagged, threw his heat up, then he straightened up and turned around. By then, I'd reloaded with a paper ctg., 165gr. 2f and a WW ball. That one only hit a 1/2 dozen willows, sounding like ftttwhock and smacked him right on the point of aim. At that shot, his butt hit the ground and he threw his antlers back over his back, shaking his head back and forth. I'd never seen such evidence of trauma before, especially with moose. They usually just take off running. He shakily gained his feet and stumbled slowly 25 feet or so and collapsed. Note he was walking, limping mind you, but on all 4 legs. His left front leg was bearing considerable weight.
The first ball, a pure lead one, had smashed the left front leg bone about 2" below the joint (difficult to be exact) and stopped against the ribs, in the connective tissue between the leg and the rib cage. I was slightly below the moose, shooting at a slight up-angle. It was not flattened out a great deal, as after hitting all those willows, I assume it had slowed considerably.
The second ball, impacting on the other side, had broken a rib off on impact, driving that 6" chunk of rib through the bottoms of both lungs, to stick between two ribs on the other side. The ball had gone through both lungs, leaving about a 3 1/2" to 4" hole, straight across both lungs, through a rib, then impacted the shoulder joint, smashing it into small chunks, stopping under the hide there. The ball is still round, with marks on the anterior surface. I was very much impressed over the 'gun's power, and the 'ability' of the leg bone to stop the first 480gr. pure lead lead round ball. What the WW ball did, in comparrison was striking! The 'chunk' of rib and velocity it must have attained to drive through the lungs and stick into the meat between the ribs was amazing. Then, to double lung the moose, go through another almost 1/2" thick rib, to smash the knuckle joint into chunks. I was impressed.
If shooting a ball smaller than about .60 be sure to hit no big bones.