Round control is very spotty on rugers and model 70's. About the only fool proof factory CRF action is a mauser 98 in its original chambering. Mauser mag box and feed lips were designed for each specific cartridge vs the generic mag boxes and feed lip setups on Rugers and Winchesters.
I agree generally with this, though the M70s seem to be more consistent than the M77s. In fact, some M77 MkIIs aren't controlled round feed at all. They are push feed with the fixed ejector. Sort of an intermediate design between the M77 push feed, plunger ejector and M77 MkII with CRF and fixed ejector.