Isaac Hollis & Sons were English gunmakers from c.1870-1900. They made some very fine guns, and you should have yours evaluated in person by someone familiar with English doubles.
Information on this weapon can be found at any reputable gun dealer. And any bookstore will have catalogs on old or new firearms.
You need the services of a professional appraiser
Isaac Hollis & Sons were noted British gunmakers from c.1860-1900. They made many top quality shotguns and rifles with many levels of ornamentation. This is one that should be individually hands-on appraised. sales@countrygunsmith.net
Impossible to say without a lot more information. It could be worth anywhere from a couple of hundred dollars to several thousand depending on the type of gun (boxlock, sidelock) and condition. Go to www.doublegunshop.com and ask there. British shotguns are very collectable and Hollis is a respected maker.
Shot shells were traditionally made with a brass head, and a body made of paper (cardboard) In new shells, the carboard is replaced by plastic. Very early shotshells, and special use shotshells were ALL brass. These were expensive and rather scarce- the brasshead/ paper body was much more common.
Alton Hollis and Patrick Hollis are brothers .
The address of the Hollis Public Library is: No. 1 Hollis School Road, Hollis, 99950 0764
The address of the South Hollis is: 204-01 Hollis Avenue, South Hollis, 11412 1899
The address of the Hollis is: 202-05 Hillside Avenue, Hollis, 11423 2297
The address of the Hollis Social Library is: 2 Monument Square, Hollis, 03049 0659
The phone number of the Hollis is: 718-465-7355.