Forgive me if I missed it, but what is it you want to do with the rifle? Hunt, shoot at distance, plink, target, something else...? How is it behaving now? Does it zero? Reliability problems? Accuracy problems that are the weapon's fault? Is it bedded, floated?
I'm not familiar with the 770, although I can gather a lot from the comments. Still, I can't imagine that it's worse than throwing rocks or going Robin Hood, is it?
Having seen some seriously sub-optimal equipment accomplishing amazing feats out here (that they have no right to do) for people determined to make them work, I've become a big believer in trying anyway. Someone who has been able to make one of those shoot well will probably be able to shoot anything well.
Someday when you get your hands on an AI, it'll be gravy lol