Bob, when comparing his Sharps ctgs. to the .62 round ball, is comparing properly stabilized as well as slightly hardened bullets to a pure lead or hardened round balls, yet he found the .62's spherical balls to be superior within range. When a person uses & compares an elongated bullet from a round ball twist barrel, to a stabilized round ball, there really isn't an even test field.
The barely stabilized slug when in the air, contrary to a stabilized one, does not consistently go through the animal in a straight line. Upon impact, the barely stable bullet becomes unstable, tumbling or often turns on tough tissue, doesn't even have to be a bone, and tends to 'course"(travel) through the soft parts of the body. I am talking about how they worked on moose in Northern BC. This 'shirking of the bones' was even found to be the case on humans as per the Surgeon General's findings on the battle field in Crimea.
I didn't see where anyone said the round balls out penetrated the conicals, but they do penetrate in the line presented, not glancing off the bones.
A 466gr. WW ball from a paper ctg. from my .69, after hitting 1/2 dozen small willow twigs, hit a rib just under the hide & fat layer on the right side of a moose, just behind the elbow, middle of the lungs. It broke off close to a 6" piece of rib bone (3/8" thick) which went through the right lung as it angled down, through the bottom centre of the left lung, sticking into the meat between ribs on the off side.
The round ball made a 3" diameter "hole" through both lungs (I assume by the shock wave), smashed the offside leg and came to rest against the hide. The moose 'caved' at the shot, staggered sideways a step and down it went. Love that gun!
I do have 2 minnie moulds for that rifle. The lighter bullet mould casts a 580 gr. hollow bases slug & this recoiled badly enough I only fired a few of them. I bored this mould to test bullets for a fast second shot. After that, I experimented with round balls loaded in paper ctgs. and found I got the same accuracy as a patched round ball at 100yards. This rifle and I were shooting 5 shot groups in the 1 1/2" vicinity at 100 meters off bags. The paper ctgs. shot identically and I could fire up to 10 of them, without any trouble loading them. As I made them, the lands impressed slightly on the balls, and were fairly tight in the bore. The wadded up paper ctg. below the ball sealed off the gasses, thus they were very accurate.
A couple other fellows from this site tried these paper ctgs. as well, in16 bore and 12 bore rifles. Their findings and accuracy were the same or similar to mine.
With practice, I was able to shoot, then "reload, cap, aim and shoot again in 8 seconds". Thus, with the use of paper ctgs. I ended up with a fast (for a ML) second shot and didn't need the slugs. I was concerned the slugs might damage/crack the stock (or my collar bone). The other Minnie mould I have but did not test other than casting a few bullets, was the .69 calibre original design, 730gr. bullet. I had no desire to try them, even with the original-type military load of 70gr.
James Forsyth's book, "The Sporting Rifle and it's Projectiles" will explain this in greater details and how HE as well as other hunters of the day, observed muzzle loaded slugs (necessarily pure lead) to work on heavy game compared to spherical balls that were hardened with tin or mercury. Yes- the round balls in these guns, penetrated better then the pure lead Minnie-type 'balls' fired from the same 'bore' guns. That is comparing pure lead slugs, to hardened round balls.
Up until the invention of breech loading guns, hardened round balls not only out-penetrated pure lead conicals but killed the game more quickly and surely as well. With the invention of fixed ammo in breech loading guns, hardened bullets could finally be used on heavy game and thus the decline started in round ball use on heavy game. The conicals then showed better penetration than hardened balls and replaced spherical balls for use in Africa and India as well as in the Americas and Europe.
My own experiences on this and that of local friends + that experience of others long before our time is good enough evidence for me that round balls are superior to conicals for our heavy game.