Look for a set of the older Tikka delux rings with the lever or crossbolt . They were highly polished and attached directly to the action . I had a set that I used to mount a scope on a Bruno .22 Hornet for a friend.
The M55 series of actions make a fine custom rifle . There are also the most accurate factory rifle that I have shot - I worked in a store that had over 200 in stock at one time . I never did get one at that time for various reasons -mostly lack of cash and other projects unfortunately.
Fine job to all on that rifle . Post more groups in the future please.
Glenn