All Brownings have serial numbers.
Comparison to known serial numbers.
The earlier the better. 1 is in the Browning Museum.
You will have to call Browning.
1981
You will need to supply the serial numbers to your shotguns to get the age of your browning shotguns correctly.
The suffix of M71 was assigned to the Browning model BAR(Browning semi-auto rifle) which was made in the year 1971 in Belgium for Browning.
Please provide the model information. Serial numbers were sequential by model only.
50-500 usd
1975
Call Browning
This would be a Browning BAR semi-auto rifle