Markings, serial number and features.
Yes
300-500m
The M69 suffix identifies your 300 win mag as being a browning BAR that was made in 1969.
100-1000 usd
You did not tell us which model. Not enough information to answer. Sorry.
50-500 usd
Need a detailed description
Around 1500
No way of answering this question without a more detailed description of the rifles overall condition,which model of browning rifle you have,and the bore,s condition.
How value is Browning 300 Win Mag Semi Automatic
You can tell if you have a Browning Gold Medallion 7mm Mag Bos rifle by checking the stamp on the side of the barrel. It will list the model, serial number, and where it was manufactured.
Unlikely that it is shot out. Have it examined by a competent gunsmith