Between my wife & myself, we have killed a few deer with Muzzleloaders. Our rifles are a Knight Wolverine, bought in 1995. I bought a bunch of Knight 260 gr. HP 45 cal. saboted pistol bullets back then and that is what we have used along with about 95 - 100 gr. Pyrodex. Our deer were shot at under 100 yards and the bullet was always effective.
Here is my wife with her last muzzleloader buck, Dec. 2012