Re: Ruger M77's
My guess is that there isn't the "body of knowledge" that exists for the M700 or even the M70 platforms. I don't see anything instrinsically wrong with the M77MKII action but there isn't much aftermarket stuff and not many/if any have taken M77's to the winner's circle. If someone did, then I think you'd see more people look at the M77 as an option. The integral scope mount system, as good as it is for hunters, limits options for tactical/precision shooters and would need to be reworked.
I have a M77MKII in .338WM and it is honestly a sub-moa rifle but the M77 action is not my first choice to build on since no one seems to have the fixturing, desire, etc..
It is the "newest" of the bolt action designs. Perhaps, like the Savage, they will eventually catch on.
Ruger itself has made some very modest attempts at developing a precision rifle from the M77 but until they address some the deficits and make a serious attempt at marketing a genuine tactical/precision rifle, people are going to buy something else.