Anybody contemplating a double rifle project of some kind might want to look at this eBay auction closing in about 7 hours. It is for a set of 20 Ga browning Superposed barrels. Look to be in good shape, except have two small bulges in the front half. If you have a 20 ga super, they could be cut off and sleeved to something smallish and low pressure. price doesn't look like it is going to be real high.

http://www.ebay.com/itm/20-Gau...&hash=item4843bd497b

Those are over and under barrels; yuck for a double rifle. Unless you like over and unders. I don't.