I believe it has to fit into a pistol to be illegal “armor piercing” ammo.
Since our republic has morphed into a banana republic police state where unelected bureaucrats write “regulations” for violating which we can be fined or imprisoned, it is slowing dawning on people that regulations and laws now mean what those enforcing them want them to mean at any given time.
Arrest the man and then decide on his crime.
We now have approximately half of the the population thinking it’s a good idea to use focus groups to pick the most most sellible charge and then manufacture the evidence to fit that charge.
What’s an illegal act in the world of firearms? Whatever they want it to be. And they don’t give a damn what the courts say because by that time they have already destroyed their target. May as well delete the word accountability from the dictionary.