I
used to be more then ready to tell you 2 inches high at 50 puts you in the bull at 100 yards. But I found that is not true. It depends on the rifle, the bullet, the powder, and the conditions you shoot.
Bingo: i scope and sight in a lot of muzzleloaders. There are too many variables to predict accurately where a gun sighted in at 50 yards will shoot at 100 yards or further. The most extreme case was a gun sighted in to hit center of a 2" bullseye at 50 yards when loaded with 100 grains of Pyrodex and a 250 grain SST bullet. The same gun with the same load shot over 4" low at 100 yards.