Barrel Browner:
Most better U.S. doubles in damascus used British damascus barrels...i.e., Lefever, LC, Parker...etc....
I personally would recommend GunBroker.com which generally has about 2,000 double guns for sale at any given time...my collection has numerous LC's which are my favorite U.S. gun for quality and appearance........quite a few LC damascus are usually for sale...as are other brands.....the trick is to find a nice one...!... Look @ GB item #136057818...

Best Regards,

Doug