That rifle was manufactured prior to 1968 when the Gun Control Act was passed. Prior to then, small caliber rifles were not required to have a serial number and mass produced ones often did not.
With the serial number that you have supplied;your Winchester model 50 semi-auto shotgun was made in the year 1957.
look on the frame
1-40,9061
Your winchester model 50 semi-auto shotgun was made by winchester in 1956.
1912
They refer to this handgun as the browning model BDA (browning double action auto) pistol.
Impossible to answer without the serial number.
I can say that the Savage model 775 light weight semi-auto shotgun was made from 1950-1965.I do not have the serial numbers by year of production.I do not believe that they are available to the public domain.
I have a Springfield model 187S .22 LR (semi-Auto, tube feed).
Please include the model of Winchester semi-auto shotgun you have so that along with the serial number I may give you the correct year of production.
Your serial number indicates that your Winchester model 100 semi-auto rifle was made in the year 1967.
your Winchester model 100 semi-auto was made in 1965.