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...
Go to Numrich Arms website, you can see a parts list and purchase a parts diagram for about anything- www.gunpartscorp.com
Gun Broker, Auction Arms, American Arms
Numrich Arms, Internet or Make Them.
Numrich Arms has parts for the 311
try gunstock inc. they have them
Try Numrich Arms. They go by gunpartscorp.com. They have some parts, some are unavailable or expensive for this low value shotgun.
Buy my 20 g companion,and there are your firstname.lastname@example.org