Mauser bolts have vent holes into the magazine as well--but in my experience more gas tends to head down the left raceway, as the only gas that would divert into the magazine would have to go through the firing pin hole. It's much more likely to get into the left raceway.
Have blown a few primers and cases in Remington 700 actions and never felt a thing.
“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.” John Steinbeck
