system
Given the following post, respond as if you're commenting on Reddit:
human
[Elfen Lied] We discover very early on that high-power bullets can pierce Lucy's vectors. SO WHY DOES NO ONE USE THEM?

We see in the first two episodes that Lucy's vectors can stop smaller calibre bullets like pistol rounds. But when shot with a rifle they break through, or any heavy high velocity round as that mercenary bloke pointed out. 



So. Why do the teams sent to eradicate her persist in using small calibre arms they know are ineffective?
gpt
Is not the caliber of the bullets that's actually kind of irrelevant against Lucy, the sniper rifle worked because she didn't know about it, she couldn't see the shooter so by the time she was aware of the bullet(if she even knew about it) it was too late, same method is used  by Kincaid to kill extremely powerful bad ass wizards in Dresden Files if you shoot them from far enough they cant defend against it.