Magnum2005,
Red Dots are not scopes , zero magnification, they are considered sights. Dots are like scopes you get what you pay for. A dot will work fine on a slug gun if you buy a good one ( I use one on mine - a Bushnell Trophy).
One thing to keep in mind is the dot size, I would not use anything over 3 MOA. This means at 100 yards the dot is covering a 3" area on the target. As the range decreases so does the coverage area i.e.. 3 MOA at 50 yards covers 1 1/2", at 25 yards covers 3/4".
Hope this helps.
