I would need to know the manufacturer of your 77B shotgun to be of any help to you.
The letter I think
I would need the type of browning shotgun you are asking about,and a serial number which you did not provide.
You will need to include the model number of your Winchester shotgun,along with the serial number to get a accurate year of production.
You will need to find out who made it first.
You need to find a gunsmith.
You will need to call Browning.
I would need more information on the gun but can come within a year or two. If you email me I can discuss the gun and then post info about your shotgun. jmann@worldpath.net Best, John Mann
you will find the answer in www.shotgunworld.com , click on "gun ID and value". you will need to be member to get the answer.
What shotgun?You need to list the maker of the shotgun,model number if there,type of shotgun(single shot,pump,semi-auto,over under,side by side.)gauge of shotgun(410,28,20,16,12)so that we can help you.
Need the maker of the shotgun
You will need the services of a professional appraiser