I had a cartridge case rupture in a Savage Model 99 chambered for 300 savage. A hole smaller than a pin head burned through the cartridge case about a quarter way up from the extractor grove. I felt a blast of gas on my face.
I was not injured at all but I was very supprised and will never forget the experience.

I have been reading a book entittled "Bolt Action Rifles" 3rd edition by Frank de Haas. In the chapter on Winchester Models 54 & 70 Mr. de Haas describes how the model 70 is a little deficient in the area gas management.
He wishs the model 70 had a gas shield like Mauser actions that have flanged bolt sleeves and wishes a vent hole added in the left side of the M70 receiver in addition to one in the right side of the receiver ring.

Mr. de Hass mentions that the lack of any gas shield on the bolt sleeve of M70 rifles can be fixed and that on page 73 in the April 1964 issue of "The American Rifleman" instructions are given on how to install a simple Mauser-type gas shield on the M70 bolt sleeve. "The outside of the bolt sleeve, just to the rear of its forward flared edge, is fitted with a shield made from a steel washer,silver soldered in place. The washer extends to the outside of the receiver to deflect outward any gases expelled rearward along the locking lug raceway.

Try contacting The American Rifeman magazine (NRA publication?) they may sell reprints of the article. A good gunsmith is probably allready aware of gas handling improvements that could be retro fitted to the M70.