This gun was manufactured by Anciens Etablissments Pieper, Leige, Belgium, c. 1905-1914. It should not be fired unless it is checked and approved by a competent gunsmith, so it's primary value will be as a mantle decoration - $150-$250. Value will depend on how good it looks over the fireplace. Large side hammers seem to add a bit to the decorator value of an old double, so maybe as high as $250 if you catch a buyer in a good mood. Old damascus barreled guns should not be fired unless a really-really good gunsmith has given it his approval and determined the correct ammunition (which you will NOT find at Walmart or any chain porting goods store).
Regent College was created in 1968.
Regent on Broadway was created in 1930.
Regent University was created in 1978.
Regent Airways was created in 2010.
Regent Inns was created in 1977.
Regent Park was created in 194#.
Regent Parrot was created in 1831.
The Regent Hotel was created in 1819.
Opel Regent was created in 1928.
Regent Apartments was created in 1937.
Regent Terrace was created in 1833.
Regent Esplanade was created in 1925.