The converted shotguns go for about $200 on the internet. Most of them are unsafe to shoot with today's higher powered ammo. You can find them for sale at either www.gunbroker.com or www.auctionarms.com.
This shotgun is in the neighborhood of 100 years old. There is fairly extensive information online available on this shotgun.
nitro hunter shotgun single barrel with exposed hammer stamped belknap hdwre and mfg serial 5516
No way to tell without more information.
describe the type of shotgun and recheck the serial number
They are date code stamped, see related links for information on the Remington Society of America.
Blue Book of Gun Values
1928, it will be date code stamped on the barrel. See related links for information on the Remington Society of America.
It's date code stamped on the barrel, see related links for information on the Remington Society of America.
They are all date code stamped, see related links for information on the Remington Society of America.
Model designation
1922, will be date code stamped on barrel, check related links for information on the Remington Society of America.
They were made from 1931 to 1949 so they are all date code stamped. See related links for information on the Remington Society of America