I have a Mossberg 500 Slugster 12 ga. pump if you are interested. It has a smooth bore slug barrel. Has flip up iron sights and a weaver style rail for optics. PM if interested.
I know that you specifically said a pump, but would you be interested in a Savage 220 bolt action slug shotgun? It is the black synthetic stock model, 22" fully rifled barrel, 2 magazines, and I have a Leupold 2-7x33 heavy duplex reticle scope mounted on it.