It should only cost a few dollars if it only needs the firing pin replaced. Your shotgun is only worth $50-$75 as a shooter (but have the gunsmith verify that it is safe) and about the same as a decorator (wouldn't need the firing pin anyway). So, economically, it's probably not worth the expense.
The American arms regulator was manufactored by Uberti. There are numerouse placesonline where you can purchase parts. the current version of the gun is the cattleman
Try gun shows, Shotgun News, Gun List, local gun shops.
it is a Stevens, parts are interchangeable...
Gun Broker, Auction Arms, American Arms
Go to Numrich Arms website, you can see a parts list and purchase a parts diagram for about anything- www.gunpartscorp.com
Numrich Arms, Internet or Make Them.
No public records
Numrich Arms has parts for the 311
Try Numrich Arms. They go by gunpartscorp.com. They have some parts, some are unavailable or expensive for this low value shotgun.
try gunstock inc. they have them
Buy my 20 g companion,and there are your firstname.lastname@example.org
Several different companies have used a variation of 'American Arms' over the last 100 years. Exactly how is your shotgun marked (all markings?) email@example.com
Depending on which parts, they may need to be made.
A FEW parts are available from gunpartscorp website.
Unlikely. Try e-gunparts.com
Numrich Arms should have them.
The 238 is similar to the 258. For parts, try gunpartscorp.com
Try your local gunsmith. The Riverside is a Stevens shotgun. If you can find out which model it is, you can probably find the wood at Numrich Gunparts
TRY THE FORUM ON GUNBROKERS.COM WEBSITE
i found a small list of parts at numrich guns and parts
American Arms was a trade name used by the H&D Folsom Company of New York on firearms they retailed circa 1900. It could have been manufactured by any of a dozen makers, but most likely by Crescent Firearms. Like any other 100-year-old tool or machine, parts are where you find them. You may be able to get parts that fit (or can be made to fit) from a local gunsmith or at a gunshow, but no one will have a catalog of parts for it.
Try Numrich Arms (www.e-gunparts.com). Look for parts for a Stevens 311 shotgun. They should be the same.