I'd not worry too much. If you intend to shoot a factory big bore much, properly bed the darn thing and go forth and shoot. If you want a wood stock 416Ruger, stick that thing in an African stock, and like Shoemaker, properly bed the darn thing and go forth and shoot. Wood is wood, and recoil forces are recoil forces. I don't believe that any of the factory designs are such that they receive a pass on stock issues when it comes to big bores. Taking the short amount of time it takes to properly bed the barreled action will greatly reduce the likelihood of such issues, and will more than pay for its small investment with years of reliable service.
The recoi lug on the Ruger is small in comparision to an M70, but it is more than ample in a 375/416Ruger if properly bedded in a strong stock.
Best
