Rifle scopes will work fine. Shotgun and muzzleloader scopes will work fine. All I usually concern myself on is eye relief. I like at least 3.8-4 inches of eye relief. Muzzleloaders can kick, and there is nothing I hate more then having a scope kiss my eye brow.

Some of my favortite scopes are the Nikon Pro Staff in 2-7x32. I do not think a better scope is made for what I want out of it. I also use a Millet Buck, Sightron S1, and a Bushnell Banner Dusk to Dawn. The Bushnell might only be $69.00 but it is a great scope so far. It is holding up just fine.