fletcher
Member
Just for convenience, linking the pictures from ambackforum:
I'm not sure why they failed from looking at the pictures (pretty small), but the surfaces look similar to a fatigue failure (it's not, though). The smooth portion from crack propagation, then the rough looking portion from the last little bit being torn away as that was the last shot the barrel could take. At the very least, some sort of error during assembly or maintenance produced a crack in the barrel. The posts about the torque tightening producing a crack seem like the best bet.
I'm not sure why they failed from looking at the pictures (pretty small), but the surfaces look similar to a fatigue failure (it's not, though). The smooth portion from crack propagation, then the rough looking portion from the last little bit being torn away as that was the last shot the barrel could take. At the very least, some sort of error during assembly or maintenance produced a crack in the barrel. The posts about the torque tightening producing a crack seem like the best bet.