Hello,
I have a Ruger M77 chambered in 220 Swift that was manufactured in 1974 and it has never been fired. I will need to take another look at it to see if it has a bull barrel. As I recall, the barrel was heavier that a standard M77, but not as thick as other bull barrel rifles I own (Model 700s).
I purchased this, and many other guns that have never been fired or only fired a few times, from an old timer that was really sick in the summer of 2013. He told me he just never got around too shooting all the guns. It's quite a list....
Anyway, if this is something you might be interested in... I will figure out which safe it is in and send you pictures and other details.
Let me know,
John