The 700 "handles" gas by containing it at the bolt's head. I have blown a few primers in 700s (and a 722) and never felt a trace of gas on my face.
Have also had primers blow (and a couple of cases) in 98 Mausers and Model 70s, including the latest 70s with the supposed gas-block on the left side of the bolt. Have felt a slight amount of gas on the left side of my face in 98's, but got quite a blast from the 70s.
