There are various differences between muzzleloader scopes and rifle scopes.
The first difference is the distance limitation. Usually, muzzleloader scopes have less than 100-150 yards whereas rifle scopes have long shooting ranges.
The magnification range is the next thing that differentiates the rifle scopes and muzzleloader scopes. Small objects are visible from a long distance through rifle scopes while muzzleloader scope only magnifies the target within 100-150 yards.
The use of power is another significant difference between rifle scope and the muzzleloader scope. The power of muzzleloader scopes is less because of the short distance shooting capability. Magnification of 2 or 3x is enough for muzzleloader range means that the target is shown two or three times bigger than its real size.
In rifle scope, the power is high because of the long distance. You can even have 10x to 20x, depending on the power and model of the rifle.
Another difference is, muzzleloader scopes are simple as compared to a rifle scope. Because of the longer distances, the rifle scope shows many other features like wind velocity and the actual distance between the target and the shooter. Alternatively, the muzzleloader scope shows the only round part at the centre and nothing else.