100-500 or so
100-1000 USD or so depending on specifics
The Ruger website shows that serial number range to be late 1974 to early 1975.
Ruger's website has extensive sn data.
Depending on condition, and WHICH version of the M77, between $250 and $500.
Go to the Ruger website. Under Customer Service, Historical Data, Rifles, M77, and the serial number groups for each year are posted there.
100-500
1990
Your Ruger model 77 dates to the year 1983 with the serial number that you have provided.
100-400
50-700 usd
Around 1981