VERY cool!
Leutenant James Forsyth wrote in his 1860 book, "The Sporting Rifle and It's Projectiles" published in 1862 that until breechloading principles were developed to handle powerful ctgs. hardened lead round balls would be the favourite for the hunting of dangerous game.
He noted in his book, that rifles on the "new" Lefaucheux principal would likely take over when they could be made to handle powerful ctgs with hardened bullets.
I did not know of this version.
Thankyou.