So they are simply a bad batch, unfit for the purpose of target ammo for miltary rifles. Already there are two degrees of separation from the army’s stewardship of the bullets – the NZ dealer and now the American one. And I am left with two questions:

Presumably they are still unsuitable for the newer civilian rifles that have a spin rate comparable to the Steyrs, so isn’t there still some risk?

Acciidants happen. If the the bullets are used for hunting, what happens on impact with an animal (or a man)?

Most civilian rifles are older and have slwer twist rifling so the bullet are not spun as fast. They do not disintergrate when fired from the correct type of barrel.

The bullets are not as strong so they will break up when they hit the ground – as a safety feature to prevent them bouncing off the ground and out of rifle ranges.

They are weak enough so they come apart if spun too fast.
But are perfectly safe to fire from suitable civilian firearms.

Having said that, the presence of thick sea-ice at the mouth of a glacier can inhibit calving for years, so that the glacial flow juts out from the mouth, sometimes so consolidated that it survives the summer melt of the sea-ice. When it finally calves, either from its own weight or from the impact of a floating iceberg, it can create a super-iceberg. That is the type of iceberg reported this year.