Ruger M77 with a Bull barrel and the twist is a ...........
1:14

Most data states that a 1:12 or 1:10 does better with the bullets larger than 64 grs......... that is why I was surprised with this group.

I tried a #1370 Sierra 63gr many years ago and it would not shoot for me using BLC, 4895, 4064, H380, 4320, H414 or 4831. No chrony back then so no fps info........sorry.