Another vid I watched about this incident. Something about the plastic on the sabot round plugging the muzzle brake causing excessive pressure in the barrel. That there are zero safety backup features on that gun isn’t helping a bit. Both issues explained in these 2 vids, from experienced people with these things.
From what I’ve seen, old ammo sometimes get more powerful as it ages. I’ve seen it go both ways.
I have heard of that before. I have little direct experience with sabots but did hear sabots should not be used with muzzle brakes. It takes very little obstruction to make pressure go to the moon.