How to definitely destroy destructible mesh with applyDamage?

I have a destructible mesh that I want to destroy in C++. It seems that applyDamage is the way to go, and I’m using this line:

destructableComponent->ApplyDamage(100, destructableComponent->GetComponentLocation(), FVector(0, 0, 1), 500);

now most of the time it works, but not always! sometimes it doesn’t break. The damage threshold is set to the default 1.0.

so what’s that about? Why does it sometimes not work? Is there a foolproof way of destroying a destroyable mesh with c++?