You must call Browning to find out.
The prefix of 4M to your serial number indicates that you have a Browning standard weight model auto-5 shotgun,which was made in the year 1964.If it was a trap model,it would be so marked.
You must add if this gun is a trap model,skeet model,standard model,golden clays model,sporting clays model before we can give you a correct price.Also include the condition of your browning as this will help quit a bit.
They are called BT-99 shotguns
Yes they did make a auto-5 trap.These were made with a 30in.full vent rib barrel and weighs 8.5lbs.these were made by FN in belguim until 1970.
You will have to call Browning since you don't mention the serial number.
your Winchester model 12 standard trap was made in 1939.
The code after the "pm" is the model type. Are you sure it says 143? Browning doesnt list a model 143 Citori, but they did have a "153". The 153 denotes the Hunting model Grade l with a 3" chamber. According to info I found, 143 indicates a trap with a Monte Carlo stock. I do not know why Browning does not list it.
You will need to call Browning,s customer service dept for the exact year of production.The model bt99 trap shotguns were originally made from 1968-1994 by Miroku of Japan.The current models were made from 2001-to present.
Browning does not release production number to the public unless it is a limited edition.
Vale 5000.- Euro Vale 5000.- Euro
The Winchester model 1912 trap shotgun was made from 1938-1964.With the serial number that you provided,your model 12 trap shotgun was made in the year 1921.It could be that yours may not be a trap model due to the date of manufacture!That being said a model 12 trap shotgun will bring between 700-1,200 dollars depending on the overall condition and a good bore.
Please add the serial, but it is likely a single barrel trap gun such as the BT99