Most frangible ammunition is made by compressing copper powder (either pure or with tin and/or polymer added) into the shape of a bullet on a machine basically identical to the kind used to manufacture medicine tablets. When a frangible round hits something hard — a steel plate, a rock, etc. — POOF! It transforms back into dust.
But just how easily does that happen? Does frangible ammo return to dust if it hits something like a car door?