Re: ruger m77 MK1 .220 swift
One of my favorite rifles is a factory Ruger K77VT Heavy barrel .220 Swift. It has, more than once, embarrassed custom rifles with it's Ruger factory sewer pipe.
That being said, you will not find much outside of a custom stock (McMillan, Manners or Stockade) because no one makes accessories for the MkI and MkII. I have two of those .220 Swifts for Prairie Dogs and Predators and I have even called Stocky's to beg them to offer their laminate stocks with the aluminum bedding block in a Ruger pattern. No dice, but, oh well.
I would throw a decent Leupold or Zeiss Conquest on it, and call it a day. I am almost positive that you have a 1 in 14" twist for the light varmint bullets (almost all Swifts were barreled in this twist, and I had to order a barrel with 1 in 8" twist for heavier bullets)and it will not be conducive to long range accuracy with the lighter bullets you will have to shoot.
That being said, you have a fine rifle, and I would shoot it as is, and would upgrade the glass, if even that.
This was a screwing around off bags three shot group at 100 yards. This was after a day of prairie dogging with the factory barreled Swift that I own, prior to cleaning. I used to have a dime with a five shot group in it, but it was lsot during a PCS move.