Check the barrel codes on the Remington Society of America.
http://remingtonsociety.com/rsa/questions/barrelcodes
it is below the feildmaster logo
OH on the barrel? that's not the serial. If it's early probably July 1961.
Check date code, see related links
When was the serial? They all have serials. They were made from 1936-54 and have date code stamps on the barrel which can be looked up on the manufacture date link on the Remington Society of America.
Check date code on barrel - see related links
1946, it will be date code (month/year - letters) on the left side of the barrel. You can look this up under the manufactured date on the Remington Society of America site.
no. the serial # will normally be 5 digits.
You need to look up the barrel codes, the details are on the Remington Society of America here: http://remingtonsociety.com/rsa/questions/barrelcodes
1949 - there is a date code on the barrel for month/year details on the Remington Society of Amerca here: http://remingtonsociety.com/rsa/questions/barrelcodes
50-150 USD or so
All 121's are date code, see related links for the table/information for looking it up.
The age of a Remington 760 Gamemaster can be determined by its serial number, as Remington used a specific dating system. The production of the Remington 760 began in 1952, and the serial numbers can help identify the year of manufacture. You would need to reference a specific Remington serial number chart or contact Remington directly for precise dating based on the serial number.