What Comfortably said. And do not be afraid of damascus barrels. A sound damascus barrel is not the hand grenade that some people claim.
Shopping for a used gun is easy. Shopping for a particular sort of used gun not so much so.
Invest in lighted arrow nocks. They are not a lot of money and they fit down most any barrel so you can see the bore. If you find one that excites your interest, ask the owner/seller if he can pull the barrel for closer examination. See if it "rings". I'd not be too put off if he refuses. Hours of manning the table at a gun show erodes my opinion of my fellow man.