The R & RS both had a stock designed by Col. Whelen that is much more scope friendly than other models.
That facilitates better shooting IME.
My R in 300 shoots MOA with several factory loads My Pet Load of the 130 TTSX over 4198 nudges 3000 fps, clover leafs 3 and is deadly.

99s in 358 are great rifles albeit serious kickers with the steel buttplate.

If of interest, I have an ANNB Stith mount (left offset) for a Lyman Alaskan to fit your 64.