I have 3 77's old style with the tang safety. Great shooting rifles and I won't part with any of them for any amount of money. One the 77 243 that used to belong to my dad is now set aside for my grand son who will be 3 soon.

I have a friend with the 77 50cal. ML. he has only put a Cabelas 209 kit on it. He I am sure would not trade it even up for any ML on the market today.
I really think Ruger brought out the 77-50 at the end of the bolt ML time frame. Bolt guns no longer sell except to a slect few that love them Like me.
I am sure that Ruger no longer makes this rifle, probably due to poor sales of it.
Don't know if they will go the BPI route like Remington and Winny? Maybe they will just stay out? Wait for a stable trend in styles and come back? Never know, but they are fine rifles & hand guns in my book.

Al