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$300-$450 depending on the condition. Based on a Mossberg 500 and manuf in 1973
This gun was made in 1949.
50-100
Your Browning sweet sixteen shotgun was made by FN of belguim for Browning in the year 1951.
Felix was a shotgun manuf. of Eibar, Spain. Side by sides were imported by Sarasqueta of North America of Coral Gables, Fla.
Manuf. or man.
If you call Colt with the sn, they will tell you.
Might be Winchester.
Proofhouse.com has Colt sn data.
Try the sn tables at Proofhouse.com
100-400 or so