Yes, the Bridge Gun Company did make several gauges of shotguns. However, these were not made by the Bridge Gun Company. It was actually made be a diffrent company and marketed under the Bridge Gun Company banner.
You can find information about Russell Arms Co. shotguns online at places like Gun Trader or at many local gun stores. You can also find information online at Shotgun World or Arms List.
The Bridge Gun co. shotguns were made by the Crescent Fire Arms Company. You can try for parts at: Numrich gunpartscorp.com Jack First jackfirstgun.com Bob's Gun Shop gun-parts.com
Nikko shotguns are made by the Japanese gun manufacturer Nikko Arms Co., Ltd. They are manufactured in Japan.
Baker Gun Co of Batavia NY
There is a lot of Information on the Baker Gun & Forging Co. They started in 1890 and made shotguns up to 1923. They made several different grades of shotguns. I suggest that you go to a book store and find a book called "2008 standard catalogue of firearms 18 edition" in it you will find several different photos of shotguns and listing of the different grades. All of them are valuable. look on page 104 for the information you are seeking.
Armory Gun Co is the trade name used by H&D Folsom Arms Co on Shotguns. Later sold to Savage Arms around 1930.
Library, internet, gun shows.
You'll probably have to find a gunsmith who can make your parts. Shotguns marked Baker Gun Co were made in Belgium or by Crescent Fire Arms, Meriden, CT, for H & D Folsom in the early 20th Century.
Bridge Gun Co was a tradename sold through Shapleigh Hardware Co. Manufacturers included H. Pieper and Anciens Etablissment Pieper in Belgium, as well as Crescent Fire Arms, Harrington & Richardson Arms, and J. Stevens Arms.
70-100 or so years old
Toledo fire arms is an old company that trades in Antique Firearms, hand guns, rifles, shotguns. They also trade in ammo, gun parts, gun safes, holsters, magazines, optics, reloading etc.