IIRC, a short action ultralight stock will work. The length of pull would be longer. I don't have one but I remember a guy at one of the sportsman clubs that did it. I would call Ruger and ask.
This is the stock he used:
http://www.midwayusa.com/product/255323/ruger-rifle-stock-ruger-m77-mark-ii-short-action-standard-ultra-light-barrel-channel-synthetic-black
I do know he did some fitting. I saw the rifle but really didn't check out the fit.
