http://www.swishercs.com/winchester/
Winchester did not make a model 77.Could you mean model 70?,or do you refer to the ruger model 77?
Your Winchester model 77 rifle was made from 1955-1963.
Watch this video.
Best left to a gunsmith
Ask a gunsmith for help
Best to ask a gunsmith for help
Your Winchester model 77 was made in the year 1958 with the serial number that you have provided.
marauder.homestead.com
What do you call your gunA Winchester 77 if a semi auto .22 rimfire, the .22 hornet cartridge will not fit and cannot be made to fit into a model 77
Highly recommend you ask a gunsmith for assistance.
You will need the help of a gunsmith.