Also known as a "Cougar".
It is a revolver. Value about $250, depending on exact model and condition.
50-350 USD or so
Ruger's website lists the current offerings.
Uncertain of the term "open the barrel". Single action revolvers such as the Ruger Bearcat are loaded one chamber at a time from the rear of the cylinder. The barrel is generally not a removable part, and is factory fitted in place. If we have totally misunderstood your question (possible) please repost, or leave a message on my message board, and we'll try to help.
Ruger makes a solid quality product
Ruger has sn information on their web site.
You need to contact Ruger. You may have a prototype
Revolver
seven hundrud
Impossible to answer without a DETAILED description of ALL markings, barrel length, finish, overall condition, box, papers, accessories.
The Black Hawk is made by Ruger, not Dan Wesson. Different gun, different value. SO- which do you have?
100-1000 dollars.