Handling a couple of R93 not long ago, I could not but notice two things:

- If, for any reason, be it the fault of the shooter/handloader/moron on duty or not, the barrel extension starts to give up, then the conical design of the bolt pushes the wedged locking fingers backwards and OUTWARDS, compounding the problem. Don't know if this ever happened, but it's a single-point failure with no plan B, and the net result is a bolt in the face of one unhappy customer.

- If, for any reason, be it the fault of the shooter/handloader/moron on duty or not (sorry to repeat myself, but I noticed that both Blaser GmbH and Blaser aficionados tend to say that whatever happens in an accident is solely the fault of the abovementioned shooter/handloader/moron on duty and definitely not of the designer...), pressure builds up between the bolt and the barrel extension too fast for the vents to evacuate it, then the locking fingers may very well be pushed back, forcing whatever lock there is that keeps them in place. Remember, that lock is just meant to keep the locking fingers in position, NOT to handle the full thrust against the bolt face. Or pressure around same bolt, if the case may be.

Again, boom-ka-boom in the face, no plan B.

Now, I've seen M98 actions from rifles blown to pieces. The actions were bent and wedged solid, the barrel had blown, the stock was history, but nothing had come backwards to hit the poor dimwit - have to be one to shoot new 8x57 JS ammo (.323 bullet) in old 8x57 rifles (.318 bore), and not notice that the first bullet got stuck in the barrel.

In which incidence can a M98 bolt from a sound action, i.e. not a butchered contraption from a backyard wildcatter, be blown in someone's face?

Where can I find descriptions of such accidents? Afterall, with the millions of Mauser systems manufactured and sold in over a century by dozens of factories, there must be some pretty good record of accidents.

All the "blown rifles" from M98 systems I've seen or heard of have ended up with splinters in the forearm and, not half a face missing...

Many designs have no Plan B or secondary breech retention feature and work fine.
Much of the safety comes from the gross design strength that may provide a 3,4, 5 to 1 or great safety factor. When the original design is so strong you get little benefit from having a secondary redundant safety feature. The old Brooklyn Bridge was the first really large cable suspension bridge. Part of the way through the engineer Roebling found out that they had been supplied substandard steel for the cable wire. He determined that if the rest of the steel was made to specification there would be no problems. Why was this so?
Roebling designed the bridge with a 7 to 1 safety factor. The substandard wire reduced the safety factor a little. With such a huge margin of error possible in the design the bridge was still safe and it still stands.

One of the things you do not know about the Blaser is the destructive testing that was performed by the designers during development. You might contact the manufacturer. They may surprise you. The barrel extension may be made of steel much tougher than any standard M98 receiver making it very difficult to destroy.

I think the the question is, as hard as it may be to KABOOM a Blaser or a Mauser, are there any cases of Mauser facial injuries as significant as those known to have happened when KABOOMING the Blaser?

I have paid close attention to this issue over the years, and know of no instances where the shooter was injured in the face from an unmodified 98 action having failed.

For the record, the bullet of an 8x57IS cartridge does not get stuck in the barrel of an 8x57I rifle. It gets stuck in the neck of the chamber, resulting in a ruptured case.

.323 bullets themselves have no problem going down a .318 barrel. It is the undersized neck of the I chamber not letting the IS cartridge neck let go of the bullet.

The Blaser R 93 also has a secondary bolt locking mechanism that is at the rear of the bolt carrier, and locks in to the metal reciever at the back of the magazine.

KurtC, That is also what happens when an 8x57
is fired in a 30/06.
Good LUCK!