I'm going to blame ammo...
I've owned lots of 22 rifles and I can say not one was ever made to detonate and explode when firing.
The only thing that could cause this is a barrel obstruction or overcharge (or possibly bullet setback although with a .22lr I think this would be very difficult).
In my opinion, if it were an out-of-battery, then the rupture would have been at the side, not the rear. The fact that it is the rear is telling me it was fully inserted into the chamber.
It's also difficult to detonate a .22 casing out-of-batter (I've tried).
Here's a test: pull a bullet, dump the powder, insert case into chamber, drop bolt, pull back on bolt slightly then squeeze trigger/drop the hammer. Did it go off?
Is it possible the round shot before the "Kaboom" was getting lodged in the barrel? Did the ammo feel/sound inconsistent? .22lr ammo is notorious for being crappy and the only stuff I like to shoot is the American Eagle bulk which seems to be consistent. I've experienced a bullet getting lodged in the barrel and still ejecting the case... very lucky I noticed it as it would be easy to miss it when firing rapidly.
*The 597 is definitely finicky, and as mentioned it does require some fine tuning of the rods to operate reliably. I believe it is generally running at tighter tolerances than the 10/22. A 10/22 will go through a few bricks with no problems, but a 597 will require cleaning as the bolt will start to slow down and get sticky.
I've owned lots of 22 rifles and I can say not one was ever made to detonate and explode when firing.
The only thing that could cause this is a barrel obstruction or overcharge (or possibly bullet setback although with a .22lr I think this would be very difficult).
In my opinion, if it were an out-of-battery, then the rupture would have been at the side, not the rear. The fact that it is the rear is telling me it was fully inserted into the chamber.
It's also difficult to detonate a .22 casing out-of-batter (I've tried).
Here's a test: pull a bullet, dump the powder, insert case into chamber, drop bolt, pull back on bolt slightly then squeeze trigger/drop the hammer. Did it go off?
Is it possible the round shot before the "Kaboom" was getting lodged in the barrel? Did the ammo feel/sound inconsistent? .22lr ammo is notorious for being crappy and the only stuff I like to shoot is the American Eagle bulk which seems to be consistent. I've experienced a bullet getting lodged in the barrel and still ejecting the case... very lucky I noticed it as it would be easy to miss it when firing rapidly.
*The 597 is definitely finicky, and as mentioned it does require some fine tuning of the rods to operate reliably. I believe it is generally running at tighter tolerances than the 10/22. A 10/22 will go through a few bricks with no problems, but a 597 will require cleaning as the bolt will start to slow down and get sticky.