If you go to the Ruger website, look under customer service, then historical documents, then rifle, and Model 77, there is a serial number list by year.
Ruger has sn data on their web site.
Ruger's website has a sn function.
1964
Made in 1950 but it's a Ruger Mark I.
Ruger's website has sn tables that will answer your question.
If the Ruger website is working, it has sn data on it.
Ruger's website has sn tables that will answer your question.
1965
50-200
It was manufactured in 1961.
Made in 1975.
Ruger will tell you if you phone customer service.