Try Browning or egunparts
I have no records of a Browning 16ga shotgun having a A prefix to the serial number.Please check and list the model number(or name model) of your shotgun in your next post.
Gunbroker
list the serial number and we can help
The browning web page does not list serials this low and or numbers with a X. Based on that list it was made in the 30's?
You should be able to find a list of gun shops in your area that may have a Browning shotgun of this make.If you do not,I would go to gun broker.com.I believe that they will list a few of this model from time to time.
Look at the serial number again as this is imcomplete. Go to Browning's site, Support, Date your firearm and they have a list of dates.
Try egunparts.
Try e-gunparts.com, Shotgun News, Gun List, local gunsmith might be able to make/modify parts.
Gun shops,craigs list,Gunbroker.com,Guns America etc.
http://www.eaacorp.com/manuals-parts-diagrams.html
Try the Gun Parts Corporation online
Many books have been published on the various models. Try Blue Book of Gun Values.