Try Numrich Arms. They go by gunpartscorp.com. They have some parts, some are unavailable or expensive for this low value shotgun.
An automatic shotgun from Sears Roebuck would top out at around $200.
Your western auto model 312AA shotgun was made by mossberg for western auto.The mossberg model 395,395K are the mossberg model designations for your shotgun.
Sears' JC Higgins Model 25 is the High Standard model A1041 .22 auto
Try e-gunparts.com
its a Remington model shotgun(semi auto)
Being that you said auto shotgun,then you have the Browning auto-5 shotgun that was made by FN in Belgium from 1903-1975.Your serial number indicates that your Shotgun was made in the year 1938.
I own that very shotgun, the model 21. I purchased a left hand safety for mine in about 1970 from a parts catalog for a High Standard that a friend had puchase. I can't tell you though if the model 20 is the same. The 21 is a variable choke slide action. I have never had a problem with it. Numrich Arms (www.gunpartscorp.com) has a cross reference section- its on the left side of their home page. You can look up a Sears or Western Auto or Montgomery Ward firearm model, and it will give you the maker, and corresponding model of that maker. Sears Model 21 evolved from the model 20. parts lists for comparing various Sears modesl are available at www.histandard.info
Which Model?
Stevens, as their Model 94.
your shotgun was made by high standard in the late 1970's to early 1980's. numerich gun parts has many parts for it available as they were able to buy most of high standard's inventory when the factor closed in 1984. you can find them at either www.e-gunparts.com or 1-845-679-2417. good luck
your browning model auto-5 shotgun is valued at between 375-650 dollars.
Odd question... It's a auto-loading shotgun made from 1905-1947, actually it is the FIRST auto-loading shotgun produced in the U.S.A. !