I've used them a couple years ago in a Great Plains percussion .50 slow twist, they worked fine for deer.
My notes remind me that I used a lubed felt wad under the bullet and I've rolled them in liquid Alox as well if the lube seemed a little thin.
Good luck

"Camping places fix themselves in your mind as if you had spent long periods of your life in them.
You will remember a curve of your wagon track in the grass of the plain like the features of a friend."
Isak Dinesen